At first glance, this should be easy. The iPhone uses the same hardware ports as the iPod, which has attracted thousands of accessories. And the iPhone uses a modified version of Apple’s Macintosh operating system, which runs numerous small programs called “widgets” that would be perfect for the iPhone.

But, in fact, using add-on hardware for the iPhone will, in many cases, require buying new gear, or at least adapters to make the old iPod gear work, because of subtle differences in the way its hardware ports work. And there is no way to load Mac software onto an iPhone — even widgets. So you have to access iPhone-specific software through the phone’s built-in Web browser.

I have been testing some of the very first crop of iPhone add-on hardware and software. Some work well, others not so much. I expect to return to this topic when the add-on market is more mature, but here is an early look.

Most of the first hardware accessories are cases and headsets, for both music and phone calls. I didn’t test any cases, though I liked the look of one from Belkin, called simply the Acrylic Case, because it has a kickstand on the back that makes it easy to watch videos on the iPhone without having to hold it upright. It costs $30.

A good guide to third-party iPhone cases, headsets and other accessories can be found at ilounge.com. Apple’s own limited selection of accessories can be viewed at apple.com/iphone/accessories.

Many headphones for the iPod won’t work on the iPhone, because its headphone jack is deeply recessed and the connectors on even expensive headphones just can’t reach in deep enough. Belkin sells an $11 adapter to solve this problem. I tested it with my expensive Shure iPod headphones and it worked.

The bigger problem is that even the costliest iPod headphones lack a microphone and a call-answering button, so they can’t handle the dual functionality of the iPhone — listening to music and conducting phone calls.

Apple includes such a combo headset with the iPhone. It looks like the standard white iPod earbuds, but includes a tiny controller, embedded in the right earbud cord, that incorporates a microphone and also acts as a button. Push it once and it answers calls or ends them. When playing music, a single push pauses a song and a rapid double push skips to the next song. I found these Apple earbuds worked very well and were much more comfortable than Apple’s old iPod earbuds.

If you want to use your existing third-party earbuds or headphones, Shure will begin selling in August a $40 adapter called the MPA-3c. It not only fits the phone’s recessed jack, but also includes a microphone and control button that works just like Apple’s. I tested it with several iPod earbuds, from Apple and others, and it worked fine, though the mic is very low on the cord and must be clipped higher up on your clothing to work optimally.

Altec Lansing has several iPhone-compatible wired headsets in the works. I tested one, the $90 UHS306, due in August, and liked it a lot. It doesn’t require any adapter and it has a combination microphone/control button mounted high up on one cord, plus a second cord-mounted controller for volume adjustment and muting.

Plantronics also plans several wireless Bluetooth headsets to work with the iPhone. Most existing Bluetooth headsets should also work, but only for phone functions. The iPhone doesn’t currently support playing stereo music through Bluetooth. I tested a new Plantronics Bluetooth headset, the $130 Discovery 665, and it worked well. It is available now. Apple will also be bringing out its own Bluetooth headset for phone calls for $129.

Many accessories, such as car audio kits and home speakers, that worked with the iPod’s bottom connector, will require a simple plastic adapter for the iPhone to fit into them. Apple sells these for $9 for a pack of three.

Other accessories that use the iPod connector won’t work right on the iPhone because they don’t reroute the sound from its speaker, a feature the iPod lacks; or because they aren’t properly shielded against interference from the iPhone’s transmitters. New versions are likely to be rolling out. These will display an Apple-endorsed label that says “Works with iPhone.”

I also tested about a dozen add-on iPhone software programs. Most were either rudimentary, pointless, or worked poorly.

There were two that I liked a lot. One is a Sudoku game, at sudoku.myiphone.pl. The second, at showtimes.optimalconnection.net, lets you look up movie show times in any zip code, and links to the phone’s Google Maps program and to the Fandango ticket-buying site.

Still, the whole system of running programs through the browser is more cumbersome and less satisfying than if you could directly install them on the phone.

You can find a growing list of iPhone software at iphoneapplicationlist.com.

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

Windows XP to Windows Vista: Microsoft has built a decent migration utility into the new Vista version of Windows. It’s called Windows Easy Transfer. It allows you to migrate folders and files, email accounts and messages, settings and favorites.

Windows Easy Transfer can be used to manage a migration over a network, via burned CDs or DVDs, or with external hard disks. But I tested it only with the simplest approach, the one Microsoft recommends: a special cable called an Easy Transfer cable. The best known of these is made by Belkin. It costs $40, and is available in electronics stores and from www.belkin.com/easytransfercable/. It works only if your old computer is running the very latest version of Windows XP, called SP2.

In my test, I first installed the software for the Belkin cable on my old Windows XP machine (Vista can handle it out of the box). I then plugged in the cable and used Windows Easy Transfer on both machines, following the instructions as I went along. The process was simple and quick. It transferred over 11,000 files totaling 10.9 gigabytes — documents, music, pictures, videos and more — in about 40 minutes. The files and settings were placed in a new user identity on the Vista PC.

Windows Easy Transfer even lets you select which items to move — and which to skip, if you want. But there are some downsides. Windows Easy Transfer doesn’t move programs, so you will have to reinstall these manually. Microsoft is testing a program that will move programs, called Windows Easy Transfer Companion. You can download it at Microsoft.com/downloads.

Also, I got a blue-screen crash shortly after the transfer completed, but the computer worked after a restart.

I also tested another program that can use the Belkin cable (or a similar cable sold by its publisher), PCMover by Laplink Software. It costs $50, or $60 with the cable, but has the advantage of moving programs, as well as files and settings. In my tests, it worked fine, transferring roughly 23 gigabytes of programs and files in about three hours. It also set up a new user identity on the Vista PC for the transferred material.

However, PCMover can only move all of your stuff. It doesn’t allow you to choose which items to move.

Worse, one of the transferred programs wouldn’t work on the Vista computer because it lacked some underlying components. Moving programs this way is a hit-or-miss proposition, because of the hideously complicated manner in which Windows stores programs on the hard disk and because some Windows programs won’t “activate,” or run, on a PC other than the one on which they were first installed.

Another alternative is a retractable cable called The Tornado, which costs $60 at www.thetornado.com. The beauty of this product is that it requires no software installation; the software is built in and just appears when you plug in the cable. The downside is that the software is entirely manual. You have to select, then drag and drop, folders and files between two windows representing the two computers.

In my tests, it worked fine, but was tedious. And unless you’re a techie, you wouldn’t be able to use it easily to transfer settings and programs, because you wouldn’t know where to find all of the files needed.

Windows XP to Macintosh: If you bought a new Apple Macintosh, instead of a Vista PC, the process of moving your files is even easier. No cable is needed. When you buy a Mac in an Apple retail store, Apple will transfer your pictures, music, movies and other documents from your Windows PC to your new Mac free of charge. If you bought the Mac elsewhere, including Apple’s online store, an Apple retail store will perform the data transfer for $75.

If you plan to run Windows on your Mac using the $80 Parallels software, from Parallels, the company will soon release the final version of a utility called Transporter. This program can transfer all the contents of a real Windows PC into the Windows environment on a Mac. But it works only over a network, and the files it moves won’t be easily accessible by Mac programs. Details are at www.parallels.com/products/desktop/transporter/.

I haven’t tested either of these procedures.

Macintosh to Macintosh: For years, all new Macs have come with an excellent built-in migration utility that, in my experience, is simple, quick and comprehensive. It works via a Firewire cable available for as little as $4 at electronics stores. It moves all types of files, settings and even programs, and lets you choose which types to move. I have used this process multiple times in recent years. It has never failed me, and typically has required two-to-five hours.

Whatever computer you buy, migration is now easier than ever, if not perfect.

Email me at mossberg@wsj.com. See video versions of my reviews at wsj.com/mossbergvideo.

But there’s more than one way to get a strong, fast Internet signal all over your house. You aren’t limited to using a single wireless router. You don’t have to install a bunch of complicated wireless “range extenders.” And you don’t have to snake networking cables through your walls.

Instead, there’s a simple alternative that’s often overlooked: Using small gadgets called Powerline adapters, you can route your Internet connection around your house over your regular electrical power lines, the ones already in your walls. It really works, it’s fast and it doesn’t disrupt your electrical system. Even better, it requires zero technical skill.

You just plug one of the adapters into a standard electrical outlet near the place where your Internet connection enters your home. Then, you connect the adapter to your wired or wireless router. Next, you plug a second, identical adapter into an electrical outlet in a distant room where you lack an Internet connection. Finally, you plug a computer (or even a wireless access point) into that second adapter. There’s no setup, no required software and no technicians or tools are needed.

When you plug in a computer into the second Powerline adapter, it’s as if that computer was right next to your cable or DSL modem and router. You are on the Internet at full speed. If you plug a Wi-Fi wireless access point into the second Powerline adapter, it will create a wireless network in and around the distant room, which multiple computers can use.

I first reviewed these Powerline adapters in 2003. I liked them, but they were a little slow and never took off. Now, however, one of the leading home network product makers, Netgear, offers a whole line of faster Powerline adapters.

I’ve been testing one of Netgear’s newest models, the XE104, which costs $100 per adapter, and I can heartily recommend it. It couldn’t be simpler or more effective. In my tests, the XE104 gave me wicked-fast connections. I tried plugging Windows and Macintosh laptops directly into the adapters in rooms where my wireless signal was weakest. I also tried plugging a Wi-Fi wireless access point into an XE104 adapter and picking up the connection wirelessly on the laptops. (An access point is a wireless gadget that takes a wired Internet connection and propagates it through the air.)

In all scenarios, the Netgear XE104 adapters delivered nearly the full speed of my Internet service, which in my case is very fast — 15 megabits per second downstream and two mbps upstream. In fact, the XE104 can handle speeds up to 85 mbps, far faster than any common connection.

You can use up to four Netgear adapters at once, and the company claims they will cover a 5,000-square-foot home. Netgear includes optional software to encrypt your Powerline connection, but this is needed only if you share an electrical system with other families.

Linksys, Belkin and other companies also make Powerline adapters, sometimes called bridges. But Netgear is the leader in this category, and I didn’t test the other brands.

The XE104 is a small, white rectangular gadget about 4 inches high, 3 inches wide and 1.5 inches thick. It carries a standard two-pronged electrical plug and mounts right into the wall outlet.

On the side, there are four standard Ethernet network ports, like the kind on your router and laptop. Netgear includes a short Ethernet cable so you can connect the first adapter to your router and the second one to a PC or a wireless access point.

The four Ethernet ports are what make the XE104 a “switch.” They allow you to connect each adapter to multiple devices. For instance, the first adapter can be connected both to your router and to a PC. The second might be connected to a PC, a wireless access point and a device like a game console.

Netgear makes a similar model without the multiple Ethernet ports, called the XE103, for $80. There’s also a costlier model that goes up to 200 mbps, though that’s overkill for 99% of people.

The company also makes a Powerline adapter with a built-in wireless access point for the distant room, the $150 WGXB102 model. This saves you the cost and hassle of buying and connecting a separate access point. But it’s slower and uses older technology. In my tests, it was less than half as fast as using the XE104 with a separate, modern wireless access point.

Unfortunately, like a lot of network-equipment makers, Netgear is clueless about naming products so that normal humans can understand what they are. The XE104 is officially called the XE104 85 Mbps Wall-Plugged Ethernet Switch. That’s like calling a table lamp the LS482 75 Watt Wall-Plugged Switched Illumination Device.

Netgear even makes it hard to find the XE104 on its Web site, netgear.com. It lists it under a section called “Bridges, Access Points, and Range Extenders.” You can buy them at computer stores and other retail outlets.

These adapters are a terrific way to clear up Internet dead spots.

• Email me at mossberg@wsj.com.

Lots of new technologies claim to be transformative, productivity-enhancing and liberating. But only a few really live up to those claims. One of them is Wi-Fi, the wireless networking technology that has truly revolutionized the way people use the Internet.

With Wi-Fi, you can get online in any room of a home or office — not just the room where your wired Internet connection lives. And you can use the Internet in airports, coffee shops, hotel lobbies and lots of other places where it wasn’t possible before.

But like a lot of technologies, Wi-Fi has been changing so fast that confusion has crept in. A new version of Wi-Fi, generally known as draft-N, promises greater speed, greater range and standardization, but may not deliver any of those things. I’ve been testing some of this latest Wi-Fi gear, with mixed results.

Linksys draft-N router

Also like some other technologies, Wi-Fi adheres to standards set by a private engineering organization called the IEEE (Institute of Electrical and Electronics Engineers), in which representatives of interested companies participate.

The current version of Wi-Fi blessed by the IEEE is called G and has a maximum speed of 54 megabits per second. This G version of Wi-Fi, known to techies as 802.11g, is built into most wireless routers (which transmit and receive Wi-Fi signals) and most laptops.

Now, the IEEE is working on a new, faster standard called N. It promises much greater speeds, measured in the hundreds of megabits per second, and much better range. But certifying this N standard is taking forever, partly because of factionalism within the IEEE.

In the meantime, the marketplace has moved on. Last year, major makers of Wi-Fi routers, like Linksys and Belkin, brought out routers that used a major advance, called MIMO, expected to be in the eventual N standard. This technology uses multiple antennas to send and combine multiple data streams into one faster, longer-range signal.

Last year, I endorsed one of these MIMO products, Belkin’s Pre-N router, which was the only Wi-Fi router I ever tested that covered every corner of my home at decent speeds, even when I used laptops with only the older G technology built in.

Now, the Wi-Fi market has moved again. The major makers have all brought out what they call draft-N routers and cards for laptops that adhere to a draft of the coming N standard that the IEEE has passed. It’s probable, but not certain, that the final N standard likely to emerge next year will comply with this draft. Similar draft-N gear will be built into new laptops later this year.

The makers are claiming that the draft-N routers will have up to 12 times the speed and four times the range of G equipment when used with compatible laptop cards. Even if you are just using a laptop with a G receiver built in, the new routers can also improve speed and range, though more modestly.

Speed is nice, but even current G maximum speeds far exceed the speed of most home DSL or cable modem connections. What’s more important to most consumers is range, or more accurately, decent speed at longer ranges. The biggest Wi-Fi problem people face is dead spots or very slow connections in parts of their homes.

I tested the new Belkin draft-N router, called the Belkin N1, in my house and compared it with the Belkin Pre-N router I bought last year and have used ever since. The new router, which I placed in exactly the same spot as the old one, was easy to set up. It has lovely, large icons on the front that tell you if everything on your network is connected and working.

But the N1 didn’t perform any better, and in some cases did worse, than the old Belkin. This was true whether I was testing it on a Windows laptop or a Mac laptop, and whether I was using the Belkin N1 laptop card or just the built-in G radios in my test laptops. The new model covered my whole house, but so did the old one.

I also tried the Linksys draft-N router, called the WRT300N, which has an antenna array that makes it look like a radar station or a submarine conning tower. The company had to help me set it up, because I use a very fast Internet service called Verizon FIOS, which the router’s program doesn’t recognize. The Linksys proved much slower than the Belkin, though this may be because of a mismatch between its settings and my Verizon service, which is used by only a few hundred thousand homes in the U.S.

My unimpressive draft-N experience is confirmed by several, more extensive tests done by some magazines and Web sites, which showed the draft-N gear to be no big deal.

There are two other problems with the draft-N systems. The manufacturers aren’t promising to upgrade them to the final N standard when it emerges. And buying them will get more complicated in the coming months, because they will be offered in a range of speeds and even in two different frequencies.

I can’t recommend the draft-N equipment over the previous round of MIMO-equipped routers. They will likely be better than your G equipment, but so were last year’s models.

• Email me at mossberg@wsj.com.

Corrections & Amplifications:

A new, faster standard for Wi-Fi wireless network connections promises speeds measured in the hundreds of megabits per second. This column incorrectly says the new speeds would be in the hundreds of megabytes per second.