You might be able to get at the desired file if you have previously uploaded it to an online storage or photo-sharing service, or emailed it to yourself. But, in many cases, you could be stuck.

Now Dell (DELL), the big computer maker, is aiming to solve that problem with a new service called Dell Remote Access. Despite the name, the service can be installed on any brand of Windows PC running Windows XP or Windows Vista to make its files remotely accessible, as long as it has a broadband connection. You can transfer, or stream, or share these files with others. You can even remotely use the host computer’s Web camera.

And some of the service’s functions also work even if your remote device is one of Apple’s (AAPL) Macintosh computers or iPhones, or a computer powered by the Linux operating system, like Dell’s own Mini netbook.

For basic functionality — making the files on one Windows PC remotely accessible from other devices — Dell Remote Access is free. If you want to use its advanced functions, like the ability to remotely control the host PC or to access other devices on your home network, it costs $9.95 a month, or $99 a year. This paid version of the service also includes the ability to share with others access to files or to devices on your network, such as stand-alone Web cameras.

You only need to install special software on the host PC whose files are to be remotely accessed. For basic file access, the remote devices require just a Web browser and a password to tap into the host computer. You can download the software, and get started with the service, at dellremoteaccess.com.

I’ve been testing Dell Remote Access for a few days, at home and on the road, and found that it works well, despite a few glitches and limitations. It’s not revolutionary — many other services and software programs do part or all of what it does, with varying degrees of technical difficulty and at varying fees — but Dell Remote Access combines a wide variety of functions into a fairly simple package. It will be available as a preinstalled option on Dell’s PCs later this year.

Dell also is hoping it will give a boost to sales of its Mini line of very small machines with limited internal storage for files.

For my tests, I installed Dell Remote Access on my home Dell desktop, an XPS One model running Windows Vista. The installation was easy and quick, except for one oddity: To use the new service, you have to uninstall a network diagnostic utility Dell installs on its machines, called Dell Network Assistant. Since I had little or no use for the utility, this was no big loss, but if you rely on it, this conflict could pose a problem.

Next, I used the Remote Access software to select folders I wanted to make remotely accessible. By default, the program assumes you want to share your documents, music and pictures folders, but I added some others. The software tests your network connection to let you know how well it’s likely to work.

I used a variety of remote devices to access this home Dell. These included a Sony (SNE) Vaio laptop running Vista, a Mac laptop and an Apple iPhone. I even tried accessing the Dell machine from a virtual Windows XP installation running on the Mac.

Some of these tests were conducted from within my home network and others were conducted from across the country.

In general, the tests went well. With the Sony laptop, and within Windows XP running on the Mac, I was able to view photos and slide shows, and stream music and videos, from the Dell in all locations. I opened Microsoft Office (MSFT) files and PDF files remotely and transferred files to the remote machines. I was even able to remotely control the Dell at decent speeds and use the Dell’s built-in camera.

The only annoyance was that every time you want to remotely control the host machine, you must download and install a small utility. You also have to leave on your home computer.

Dell’s system provides more limited functionality if your remote machine is a Mac using Apple’s operating system, or a Linux machine or a mobile phone. With these setups, you can only view, stream or transfer files only from the main host computer. You can’t do remote control or view cameras.

But these limited functions did work pretty well on the Mac and the iPhone, although in some cases I had to first download a song to the Mac before it would play, rather than simply streaming it directly from the Dell.

But Microsoft Word documents stored on the Dell opened right up on the Mac. It was particularly impressive to be able to view a document or photo stored on the Dell from an iPhone thousands of miles away.

Dell Remote Access is a worthy service that’s worth a try.

Find all of Walt Mossberg’s columns and videos online, free, at the All Things Digital Web site, walt.allthingsd.com. Email him at mossberg@wsj.com.

Beginning this summer, as soon as next month, wireless Internet access will arrive in the passenger cabins of some commercial U.S. airliners.

On these Internet-equipped planes, any passenger with a Wi-Fi enabled laptop — or a cellphone with Wi-Fi — will be able to do almost everything he or she could do online at home or at the office. That includes surfing the Web, using email, having instant-messenger text chats, downloading and uploading files, and streaming video and audio.

In fact, I did all these things a few days ago on a test flight using the new system, called Gogo. During the flight from San Francisco to Denver, on a small test jet, I could operate online as if I were sitting at my desk, or in a Starbucks. I used Dell (DELL) and Apple (AAPL) laptops, a BlackBerry (RIMM), a Windows Mobile phone and an iPhone to perform all the most common online tasks, while soaring over majestic mountains and glorious national parks.

I sent and received emails on Microsoft (MSFT) Outlook and Apple Mail, including messages with hefty attachments. I conducted IM chats on AOL (TWX) Instant Messenger and Google (GOOG) Talk. Using all the major Web browsers, I called up dozens of Web sites, and watched video clips on Hulu and YouTube. I downloaded photos, songs, PDF files and Microsoft Office documents. I used all the Internet functions on the iPhone, and on the Wi-Fi-equipped BlackBerry and Windows Mobile phone.

One important caveat: Gogo is a data-only system. It doesn’t allow phone calls and will block all services that allow voice conversations to be made over the Internet.

Gogo will launch on three American Airlines (AMR) routes, likely in July. The first planes to use it will be American’s 15 Boeing 767s flying between New York and Los Angeles, San Francisco and Miami. Later in the year, Gogo will be available on all of Virgin America’s small number of routes, and possibly additional American routes, if the first deployment works well. It’s supplied to the airlines by a Denver-based company called Aircell, which says it is in negotiations to offer the Gogo service on several other major U.S. airlines by next year.

The Gogo service will cost a flat fee of $12.95 for flights of three hours or longer, and $9.95 for shorter trips. You log into Gogo as you would any commercial Internet service, registering on a special Web page. Aircell plans to allow advance sign-up, so you’d only have to enter an ID and password on the plane. No add-on software, hardware or cables are required.

A few Web functions will be offered free from Gogo, including access to the American Airlines Web site, to Frommer’s online travel guides and to a limited selection of articles from The Wall Street Journal.

Gogo isn’t the first in-plane Internet service. A few years ago, Lufthansa (LHA.MU) offered a satellite-based service from Boeing (BA), mainly on over-ocean flights, but it was canceled.

The service operates at respectable, if not blazing, speeds — similar to what you’d get on a cellular broadband service or a slow home DSL line. On my test flight, download speeds varied from 266 kilobits per second to about 1.4 megabits per second, with the most typical speeds hovering between 500 and 600 kbps. Upload speeds were between 250 and 300 kbps. I found that most of the tasks I tested, except for streaming video, felt smooth and normal.

Speeds could degrade on a large plane with scores of people online simultaneously. But Aircell claims it has the technology to make my experience representative for anyone doing common tasks, such as Web surfing and email. During my test flight, eight laptops and six Wi-Fi-enabled smart phones were using the system simultaneously. All registered decent speeds, except for a couple of minutes when the plane was crossing between the zones controlled by the company’s ground-based towers.

Aircell gets Internet access to the planes through a network of 92 towers scattered across North America. These essentially are cellphone towers, carrying a high-speed cellphone data signal, except that the Aircell antennas point up, into the sky. A receiver on the underside of the aircraft picks up the signal, which is then distributed through the plane via Wi-Fi.

The companies say Gogo is safe and won’t interfere with the plane’s operation. It is government-approved, and pilots can shut the system off should they deem it necessary.

Gogo has some limitations. The service plans to allocate its capacity so that low-bandwidth activities like Web surfing and email take priority over high-bandwidth ones like streaming video. That means you may find video to be slow and halting.

And Gogo is a North American, land-based service only. It won’t work over the oceans and, for now, it won’t work on other continents.

But for U.S. travelers who want to stay connected in the air, Gogo does the job.

• Find all of Walt Mossberg’s columns and videos online, free, at the new All Things Digital Web site, http://walt.allthingsd.com. Email him at mossberg@wsj.com.

These types of attacks are called “social engineering,” and they are used by criminals to steal your money and identity, and to plant on your computer malicious software that can be used to keep ripping you off. Social engineering is the online equivalent of an old-fashioned con game, in which a crook frightens people with false warnings, or tempts them with false promises, and then robs them.

While viruses and spyware overwhelmingly afflict Microsoft’s (MSFT) Windows users and spare users of Apple’s (AAPL) Macintosh computers, social-engineering schemes can ensnare Mac users as well. There’s nothing inherent in Macs that makes their owners more resistant to falling for social-engineering scams.

The most common form of social engineering is called phishing, a one-two punch using both email and Web browsing to trick people into typing confidential information into Web sites that look like the sites of real companies, especially financial institutions. But these phishing sites are actually skillfully designed fakes that transmit your sensitive data to criminals, often in distant countries. Once these creeps have your passwords and account numbers, they can loot your funds and steal your identity.

Here are some tips to help you avoid being the victim of social engineering, updated from a similar column I wrote in 2006. It includes information on some antiphishing software that wasn’t available back then. But remember: Security software alone can’t save you from scams.

1. Never, ever click on a link embedded in an email that appears to come from a financial institution, even if it’s your own bank or brokerage and even if it looks official right down to the logo. The same goes for payment or auction services, like PayPal or eBay (EBAY). Don’t do this even if the email asserts that your account has a problem, or that the bank has to verify your information. And certainly don’t enter any passwords, Social Security numbers or account numbers directly in an email.

These types of emails are almost always fakes, and the links they contain almost always lead to phony Web sites run by criminals. The only exception might be a confirmation email from a brokerage firm concerning a trade you know you made minutes before. Even legitimate-looking addresses in emails or in the address bar of Web browsers can be fakes that hide the crooks’ true Web addresses. The lock icon on a Web site can also be falsified.

If you are truly worried about your account, call the bank or company, or go to its Web site by manually typing in its address or by using a well-established bookmark in your browser that you created yourself.

2. Don’t click on links to offers for free software or goods that you receive in an email, especially from a sender or company you’ve never heard of.

3. Never download software from unfamiliar Web sites unless you are absolutely sure you need it and it’s legitimate. Even if it claims to be a useful program, it may very well be a malicious application like a “key logger,” which can report back to crooks everything you type into your computer. If you really want the program, do a Web search on it first, to see if others have reported it as a malicious fake.

4. If a Web site tells you that you need to download special viewing software to see its videos, don’t do it. Even if it claims to be giving you legitimate viewing software, like Microsoft’s Silverlight, Adobe’s (ADBE) Flash or Apple’s QuickTime, don’t download it there. Go to the official Microsoft, Adobe or Apple Web sites to get these viewers.

5. Use a Web browser, like Internet Explorer 7 on Windows, or Firefox 2.0 on Windows or Mac, that includes built-in features to warn you about, or block access to, known phishing sites. The next versions of these two browsers will have even stronger features that will detect sites that are not only fake, but which are known to distribute malicious software.

Unfortunately, the third major browser, Apple’s otherwise excellent Safari for Mac and Windows, lacks any such antiphishing detection, though I expect Apple to add the feature in a future version. So, for now, Mac users worried about phishing should rely on Firefox.

6. Consider security software that tries to detect and block phishing sites. McAfee’s (MFE) free Site Advisor and paid Site Advisor Plus products do a good job. Symantec (SYMC) has similar features built into its large security suites, Norton 360 2.0 and Norton Internet Security 2008.

7. Educate yourself by reading about social engineering and phishing and how to avoid being a victim. Microsoft has a very good guide at: microsoft.com/protect/yourself/phishing/identify.mspx and Symantec has one at: symantec.com/norton/clubsymantec/library/article.jsp?aid=cs_phishing.

Follow these tips and you’ll be a happier — and safer — surfer.

Find all of Walt Mossberg’s columns and videos online, free, at the new All Things Digital Web site, http://walt.allthingsd.com.

• Email him at mossberg@wsj.com.

There are two models for this legal Internet distribution. Some shows and movies can be purchased or rented from services like Apple’s iTunes or Amazon’s Unbox. You pay a fee for these downloads, which don’t have commercials, and you can keep any videos you buy to watch repeatedly even without an Internet connection.

The other model, common on the Web sites of the TV networks, is free, ad-supported streaming directly within a Web browser. In this approach, you pay nothing, but you have to watch commercials that can’t be skipped. You must be connected to the Internet while watching, and you don’t get to keep the video.

This week, the ad-supported, streaming approach took a big leap forward with the launch of a Hollywood-backed service called Hulu, at hulu.com. Hulu aims to be a legal, one-stop shop for streaming of TV shows and movies from numerous networks and studios. It’s intended as an attractive antidote to pirate sites and to Google’s YouTube service, which has angered the media companies by allowing users to post all or parts of movies and TV shows without permission or payment.

Hulu is a joint effort of two big media conglomerates, NBC Universal and News Corp., each of which operates multiple networks and studios. (News Corp. also owns The Wall Street Journal and the Web sites where this column is published.) But Hulu contains programming from other companies as well, including Sony and Time Warner. All told, it offers full episodes or clips from about 400 TV series, plus 100 feature films.

I’ve been testing Hulu, and I am very impressed with its design and ease of use, and with the fact that it allows users to edit and re-publish its content on their own sites. Despite some drawbacks, it’s the first Web property I’ve seen from mainstream studios or networks that shows a real understanding of both modern Web design and the Internet’s culture of sharing. In my view, it’s far better than the typical network or studio Web site.

Even though Hulu lacks programming from ABC, CBS and many cable networks, it has a fair selection of popular shows, such as “30 Rock,” “The Office,” “The Simpsons,” “Battlestar Galactica” and “Saturday Night Live.” Its movie catalog includes old favorites like “The Usual Suspects,” “The Big Lebowski” and “Sideways.”

The site is organized in a clean, elegant manner. You can browse shows alphabetically, by genre or by network, or you can use an excellent search system. The search system even brings up links to videos of shows on other sites, such as ABC’s “Grey’s Anatomy,” that are missing from Hulu’s own collection.

Watching the material is a pleasure. You can view it in a fixed window or in full-screen view. You can also “pop out” the viewing window so you can place it anywhere on your screen and resize it to your liking. A feature called “lower lights” grays out everything on the computer screen but the video itself.

Even the advertising is relatively painless. TV shows contain just 25% of the commercial time that’s on regular TV. And Hulu allows you, in some cases, to choose the advertisers whose commercials you see, or else to opt to watch a movie trailer at the start of a video in exchange for seeing no further ads during that viewing.

In a break with Hollywood’s past rigidity, Hulu makes it easy to share, even edit, shows and clips. You can repost an entire video, or any portion of it, on your own blog or on social networking sites.

But Hulu also has some major downsides. Most important, Hulu lacks depth. Even with TV series from its owners’ own networks, Hulu typically contains only a small number of full-length episodes, and mainly offers short clips. In some cases, episodes expire after a while. For some shows, such as “Saturday Night Live,” there aren’t any full episodes, only clips. And the wildly popular “American Idol” isn’t in Hulu at all, even though it airs on News Corp.’s Fox network.

This stands in stark contrast to the depth offered on iTunes, where you can find multiple seasons of full episodes of many shows. And it doesn’t begin to compete with pirate sites, where you can find nearly everything.

Also, Hulu requires a decent broadband connection — a speed of at least 1 megabit per second is recommended, and even higher speeds are needed for some content. That means that using Hulu over the slowest DSL lines or cellphone modem cards will likely provide a poor experience.

Another problem is that, unlike iTunes or Amazon Unbox, Hulu can’t be used via a TV set-top box or a portable player. And shows can’t be saved for offline viewing, such as during flights.

Still, Hulu is a good start for Hollywood in finally providing a better experience for Internet streaming of TV and movies. If the service can add a lot more content and make viewing possible in more scenarios, it might strike a real blow against piracy.

Email me at mossberg@wsj.com. Find all my columns and videos online, free, at the new All Things Digital Web site, http://walt.allthingsd.com.

The new aluminum-clad MacBook Air, which I’ve been testing for several days, is billed as the world’s thinnest notebook computer. Its thickest point measures just three-quarters of an inch, which is slimmer than the thinnest point on some other subnotebooks. And it employs some innovative software features, such as fingertip gestures for its touchpad that are similar to those on Apple’s iPhone.

Apple refused to make the most common compromise computer makers employ to create their littlest laptops. Other subnotebooks — a category generally defined as weighing three pounds or less — have screens of just 10 to 12 inches and compressed keyboards. The three-pound MacBook Air, by contrast, features a 13.3-inch display and a full-size keyboard.

It’s impossible to convey in words just how pleasing and surprising this computer feels in the hand. It’s so svelte when closed that it’s a real shock to discover the big screen and keyboard inside.

But there’s a price for this laptop’s daring design: Apple had to give up some features road warriors consider standard in a subnotebook, and certain of these omissions are radical. Chief among them is the lack of a removable battery. So, while the MacBook Air will be a perfect choice for some travelers, I can’t recommend it for all. It really depends on your style of working on the road and what features you value most.

The MacBook Air, which will be available next week, costs $1,800 with an 80-gigabyte hard drive and a generous two gigabytes of memory. A second model, with a faster, cutting-edge, 64-gigabyte, solid-state drive and a slightly speedier processor, costs a whopping $3,100. The $1,800 price for the main model isn’t unusual in subnotebooks, which can easily top $2,000, although some competitors cost less.

In my tests, the MacBook Air’s screen and keyboard were a pleasure to use. The machine felt speedy, even with multiple programs running. And the laptop has the same Leopard operating system, superior built-in software, and paucity of viruses and spyware that I believe generally give the Mac an edge. I was able to install and run Windows XP using the third-party Parallels software.

But then there are those trade-offs. The sealed-in battery means you can’t carry a spare in case you run out of juice, and you have to bring it to a dealer when you need a new one. There’s no built-in DVD drive. The thin case can’t accommodate a larger internal hard disk. And the machine omits many common ports and connectors.

The MacBook Air

There’s no Ethernet jack for wired broadband Internet connections and no dedicated slot for the most common types of external cellphone modems. That means that out of the box, the MacBook Air has only one way to get on the Internet — through its fast, built-in Wi-Fi connection. If you’re out of Wi-Fi range, you’re out of luck, unless you buy an optional, $30 add-on Ethernet connector or a cellphone modem that connects via USB.

In fact, the MacBook Air has only three connectors: a headphone jack, a single USB port and a port for connecting an external monitor.

That single USB port is a problem, because so many peripherals use USB. You can buy a tiny, cheap USB hub that adds three more ports, but that’s yet another item to carry.

The lack of a DVD drive is partly solved by some clever software Apple included that lets you “borrow” the DVD drive on any other Mac or Windows PC on your network, so you can transfer files or install new software from a CD or DVD. This worked fine in my tests, in which I installed several new programs from CDs on remote computers, but it requires disabling third-party firewalls on Windows machines. It also doesn’t work for installing Windows on your Mac, for watching DVDs, or for playing or importing music. For those tasks, you need an external DVD drive. Apple sells one for $99.

In my standard battery test, where I disable all power-saving features, set the screen brightness at maximum, turn on the Wi-Fi and play an endless loop of music, the MacBook Air’s battery lasted 3 hours, 24 minutes. That means you could likely get 4.5 hours in a normal work pattern, almost the five hours Apple claims.

But the MacBook Air has another downside: its screen height. Because of the larger screen, the lid stands higher when opened than on most other subnotebooks. So it isn’t as usable as some competitors when the seat in front of you in coach on a plane is reclined.

If you value thinness, and a large screen and keyboard in a subnotebook, and don’t watch DVDs on planes or require spare batteries, the MacBook Air might be just the ticket. But if you rely on spare batteries, expect the usual array of ports, or like to play DVDs on planes, this isn’t the computer to buy.

• Email me at mossberg@wsj.com. Find all my columns and videos online, free, at the new All Things Digital Web site, http://walt.allthingsd.com.

And the cellular broadband services, such as Verizon Wireless’s BroadbandAccess, can operate at speeds roughly equivalent to, and sometimes well beyond, the speed of basic wired home DSL service. That means you can surf the Web, and get email and large attachments pretty efficiently.

The card for the Verizon network

A small percentage of users hook up to these cellular broadband networks using laptops that have the necessary gear built in. Another small group uses a cellphone as a modem. But most users of these networks use external cellular-modem cards that plug into a standard slot on the side of their laptops. Therein lies a problem.

The computer industry is in the process of dumping that standard slot, called a PC Card slot, for a new, incompatible slot called ExpressCard. So, buyers of many new laptops are finding their cellphone modems are obsolete.

Now, Novatel, a leading maker of these cards, has come out with a couple of new ExpressCard versions for cellular broadband networks. One, which works on Verizon Wireless’s network, is already on the market, sold by Verizon and by Dell. The second, which works on Cingular’s BroadbandConnect high-speed network, will go on sale from Dell and possibly Cingular later this year, likely late November.

I have been testing the Verizon version of the card, called the V640, as well as a pre-release model of the version that works with Cingular, which Novatel calls the Merlin XU870. The tests not only gave me a chance to evaluate the cards themselves, but also to compare the Verizon and Cingular high-speed networks.

My verdict: The cards were easy to set up and use, and worked well. But the two high-speed networks are very different. While Cingular gave me higher speeds than Verizon in a couple of locations, the Verizon Wireless BroadbandAccess network crushed Cingular’s BroadbandConnect in most places I compared them.

This wasn’t a rigorous scientific test. I used two different laptops, an Apple MacBook Pro and a Dell Latitude D820. The Cingular tests were all conducted on the Dell, because the Mac software for the Cingular card won’t be ready until the card goes on sale. The Verizon tests were all conducted on the Mac. On both machines, I used the test service at speakeasy.net, accessed via the Firefox Web browser.

Also, I tested the cards in only Washington and New York City, and on Amtrak’s Acela Express trains in between. That is a heavily populated region; it’s also Verizon’s home territory, and Cingular might have done better in other parts of the country. Verizon has been rolling out its high-speed network since 2003; Cingular is well behind. Verizon offers the service in 185 metro areas; Cingular is in just 75.

Both cellphone carriers charge $60 a month for unlimited data service using the cards, if you have a voice plan with them. The new Verizon card costs $180. The new Cingular-compatible card is likely to cost $50 more.

The cards look nearly identical, and each works on both Windows and Macintosh computers. On Windows, you must connect using special software. On the Mac, you can simply use integrated software from Apple, if you choose. Both cards have small flip-up antennas and indicator lights. Both worked fine.

Verizon’s high-speed service is often called EVDO, for its underlying technology. Cingular’s service uses a technology called HSDPA.

In my tests, which involved about 20 head-to-head comparisons, the Verizon card and network averaged 818 kilobits per second “downstream” (to get Web pages, and to receive email and attachments) and 113 kbps “upstream” (to send email and files).

By contrast, the Cingular-compatible card averaged just 463 kbps downstream and 77 kbps upstream. Plus, during the three-hour train trip, Cingular disconnected me, or simply had no coverage at all, eight times. Verizon did so only once. Verizon has a deal with Amtrak that supplies data service inside the trains, which helped, but this in-train signal doesn’t include the high-speed EVDO service.

Cingular did beat Verizon in two places: my hotel in New York’s financial district and my office in downtown Washington. In the hotel, the Cingular service got a downstream speed of 1753 kbps — its highest in my tests — versus 888 kbps for Verizon and just 747 kbps for the hotel’s expensive wired Internet service. In my office, Cingular got 1133 kbps downstream versus 644 kbps for Verizon.

But the downstream speeds varied wildly. In Trenton, N.J., the Cingular service managed just 16 kbps. The best for Verizon was 1366 kbps in New York’s Penn Station, while its worst was 132 kbps between big cities in New Jersey.

I recommend both new cards. But unless you live, work and travel in very strong Cingular coverage areas, Verizon is the better choice for high-speed wireless data, at least today.

Email me at mossberg@wsj.com.

These wireless broadband connections, available over a wide swath of the major metropolitan areas where they are offered, have been sold by two big cellphone companies, Verizon Wireless and Sprint. Both charge $60 a month for unlimited use of the services, which Verizon calls BroadbandAccess and Sprint calls Mobile Broadband. Both companies’ services are based on a technology called EV-DO, which stands for Evolution-Data Only.

This is a revolutionary development. It means that, with a properly equipped laptop or smart phone, you can now get enough speed on a wireless connection to do everything you would do with a fast Internet connection at your desk — stream video, download large Web sites, open large email attachments. And you don’t have to shell out $4 for a Venti latte just to gain access to a Wi-Fi hot spot.

Not only that, but these fast, new networks have, for the first time in years, given the U.S. the edge over Europe in cellular wireless data networks. Actual speeds on the EV-DO networks tend to be 600-700 kilobits a second, which is double or triple the actual speeds of the fastest widely deployed cellphone networks in Europe. Even the lowest speed the U.S. companies promise, 400 kbps, is faster than the maximum speed of today’s common European systems.

Now, this American trend has taken another step forward. Last month, Cingular Wireless announced it is leaping into the broadband wireless arena. It rolled out a service called BroadbandConnect to compete with Verizon and Sprint.

Like its competitors, Cingular is charging $60 a month for unlimited use of its service, and it is promising speeds averaging 400-700 kbps — about what you’d actually see with the slowest home DSL services. But Cingular’s new offering is based on a different technology, called HSDPA, for High Speed Downlink Packet Access. It’s the successor technology to the one being used today in Europe.

Because of its late start, Cingular’s wireless broadband service is much less widely deployed than its Verizon and Sprint competitors. It is available in only 16 major cities — Austin, Texas; Baltimore; Boston; Chicago; Dallas; Houston; Las Vegas; Phoenix; Portland, Ore.; Salt Lake City; San Diego; San Francisco; San Jose, Calif.; Seattle; Tacoma, Wash., and Washington, D.C.

By contrast, Verizon’s wireless broadband service can be used in 180 major markets, and Sprint’s covers more than 100. But Cingular is planning to have most major markets online by year end. Currently, the service is available on laptops using special wireless modem cards Cingular is selling for $99, after rebates. Eventually, it will also be available on smart phones.

I’ve been testing the Cingular BroadbandConnect service on a laptop around Washington, and I like it. It’s very fast — a bit faster, in my tests, than Verizon’s service. And it proved reliable, connecting properly every time. In tests in both downtown D.C. and a suburb about 15 miles away, the Cingular service averaged 640 kilobits a second, roughly 6-7 times the speed I have seen with EDGE, the company’s older data service.

In my tests, I used both of the laptop cards so far available for the service, the Sierra Wireless AC860 and the Novatel U730. Both did the job, but the Sierra model was consistently faster. In the same location, on the same laptop, within the same 30-minute period, the Sierra card averaged 689 kbps while the Novatel card averaged 449 kbps.

This may be because the Sierra card has a long, thin protruding antenna while the Novatel model uses an internal antenna. But the Sierra design can be annoying. You have to remove the antenna for safekeeping when it’s not in use, lest it snap off and get lost.

Like similar cards for Verizon and Sprint, these Cingular modems pop into the card slot on the side of your laptop. So far, they work only with Windows machines, not Macintoshes. And they require software supplied by Cingular to connect to the network. The company says Lenovo and Dell plan to build modems for the Cingular service into some laptop models later this year.

Why would you prefer a service like this to just using Wi-Fi? I love Wi-Fi, and it can often be even faster than these new networks from the cellphone companies. But with Wi-Fi, you have to find a hot spot, and you usually have to sign up with an access provider, which may charge high hourly fees and may not have service at the next hot spot you visit.

The biggest downside of the Cingular service — and those of its competitors — is cost. The $60 monthly tab, which usually requires purchase of a voice plan as well, is higher than what wired home broadband typically costs.

But if you are a frequent business traveler, it can pay for itself pretty quickly by allowing you to forgo the typical $10-$12 daily fee for Internet connections in hotels. And it can be a lifesaver if you really need fast Net access in some location where Wi-Fi isn’t available.

Citywide wireless broadband is now real — and widely available — in the U.S. Take that, Europe.

• Email me at mossberg@wsj.com.

Some people place files on a portable device, and then manually copy the files to all their PCs. Others email selected files to themselves. But these methods are time-consuming and imperfect.

Now, new services can automatically keep certain folders and files synchronized among your multiple PCs, without any work on your part.

These file-synchronization services aren’t free, and they do take a little effort to set up. But once they are up and running, the effect is like magic. Within minutes, or even seconds, after you have added or deleted or altered a file on one of your computers, the change is perfectly replicated on all your other machines.

There are three main contenders in this budding field. One, called Groove, available at groove.net, is owned by Microsoft. It’s mainly designed for collaboration work in big corporations. Two others, BeInSync and FolderShare, are aimed directly at consumers and small businesses. BeInSync is from an Israeli company called BeInSync Ltd., and is available at beinsync.com. FolderShare is from an Austin, Texas, company called ByteTaxi Inc., and is available at www.foldershare.com.

The best choices for consumers are the two consumer-focused offerings, BeInSync and FolderShare. Either will work well in most cases. But for this review, I concentrated on FolderShare because it’s faster and more flexible. In particular, it’s the only one that works on both Windows and Apple Macintosh computers.

Here’s how FolderShare works. Starting with one computer, you select the folders you want to keep synchronized. You link these folders to companion folders you select, or create, on the other computers, and install the service’s software on each machine. The software, which runs quietly in the background, transfers files, as needed, among the machines so the contents of those folders remain up-to-date and identical on every computer. The transfers, done over the Internet, are fast, invisible and encrypted for security.

Over the past few months, I’ve been using FolderShare on six of my computers — three Windows PCs and three Macs. Two of these computers are in my office; three are in my home; and one, a laptop, is often with me on the road.

I set up FolderShare to keep five different folders, containing over 36,000 files, synchronized, and it did so without breaking a sweat. For instance, I linked folders called “columns” on every machine, and linked the “My Music” folders on my three Windows machines to the “Music” folders on my three Macs.

Now, all the latest versions of my columns and notes — including those in Microsoft Word, Excel and PowerPoint files, and Adobe PDF files — are on all my Windows PCs and Macs. So are all my music files, my photos and my videos. After I wrote this column on my laptop in California, it was instantly replicated on all my other machines on the East Coast. (The use of broadband is highly recommended for speed.)

FolderShare did all this without slowing the performance of my computers, except for the first few hours, when it was moving thousands of files around in a short period.

FolderShare can handle older versions of Windows back to Windows 98. BeInSync works only on PCs running Windows XP or Windows 2000.

There are three versions of FolderShare; each can be used with an unlimited number of computers. The free “basic” version allows you to synchronize two folders, with up to 500 files in each. The personal version, at $50 a year, expands this to 100 folders with up to 20,000 files in each folder. The professional version, $100 a year, allows 250 folders with up to 50,000 files in each. It’s also speedier than the others.

FolderShare also allows you to invite groups of other users to share some or all of your synchronized folders. I tested this and it worked well. In addition, in the top two versions, you can tap into your computers from any Web browser on any computer to retrieve any file. This feature also worked fine in my tests, but you can disable it if you are worried about outsiders gaining access to your files.

If you have desktop search software on your computers, FolderShare can do a unified, combined search for files across all these machines.

FolderShare doesn’t keep copies of your files on its servers, but it does keep records of your computers, and the folder and file names being synchronized. It can provide a form of backup; your key files are on other machines if one fails or is stolen. But take care to guard your password, as anyone who learns it could access your files by logging into your account.

BeInSync has one major feature FolderShare lacks. In addition to synchronizing files, it can synchronize some of your email in Microsoft Outlook, and your contacts in Outlook and Microsoft’s Outlook Express. BeInSync also costs less. Its top version is $60 a year, or $100 for two years.

FolderShare is so useful and works so well that I recommend it or BeInSync for anyone who needs key files kept up-to-date.

• Email me at mossberg@wsj.com