Wireless cellphone earpieces can make people look faintly ridiculous as they stroll down the street or around the office, seemingly talking to themselves with ugly appendages sprouting from their heads. The pulsing blue lights on these things can make people look like robots. And these battery-powered gadgets, which use a power-hungry wireless technology called Bluetooth, are just one more thing to charge.

But such headsets are becoming more necessary, at least in the car. A growing number of cities and states are requiring all calls made while driving be conducted in a “hands-free” manner. Two more big states, California and Washington, will begin enforcing such laws in July. Unless drivers in these places have cars with costly built-in Bluetooth speakers and microphones, many will turn to wireless earpieces to make calls legally.

Now, two of the most important wireless earpiece makers are bringing out new models that attempt to make their products more attractive and functional. One is a new version of the Jawbone, which has become a leader in the high-priced end of the market. The other is a new model from Plantronics (PLT), which vies with Motorola (MOT) as the top seller of wireless earpieces.

I’ve been testing both the new $130 Jawbone, and the $150 Plantronics Discovery 925, and both work well, despite some drawbacks. Each worked properly with both an inexpensive Motorola Razr phone from Verizon (VZ) and a sophisticated Apple (AAPL) iPhone from AT&T (T). But I preferred the Jawbone, because of its technology and design.

The new Jawbone, made by a closely held San Francisco company called Aliph, is 50% smaller than the original Jawbone, which I reviewed in 2006. It continues to boast the original Jawbone’s signature feature: a remarkable ability to suppress background noise and isolate the wearer’s voice.

Jawbone performs this feat by using a sensor that touches your skin lightly to identify your voice through the vibration of the bones in your face. Using this information, its microphone can more easily distinguish your voice from background noise, and accurately suppress the latter.

This feature, originally called “Noise Shield” and now theatrically renamed “Noise Assassin,” really works. When the company first showed off the original Jawbone, it made live calls standing in front of things like weed whackers and boom boxes, and then turned the bone-sensing feature on and off to show the dramatic difference.

Aliph’s new Jawbone

In my tests of the new, much smaller Jawbone, I stood a few feet from a roaring vacuum cleaner, while on a phone call. The person I was calling could barely hear me with Noise Assassin turned off, but could clearly make me out when I turned it on.

By contrast, the Plantronics Discovery failed my noise test. It was useless anywhere near the vacuum cleaner. This was obviously an extreme case, but it served as a stand-in for other loud noises likely to be encountered in real life, like large trucks, or construction gear on the streets.

The biggest flaw in the original Jawbone, in my 2006 tests, was its performance in wind, which was poor. The Jawbone did much better in my latest tests. During a Jawbone call from a car with all the windows down and the sunroof open, my voice was easy to make out, according to the person I was calling. The new Plantronics earpiece did just as well in this wind test.

Plantronics claims its headset also enhances the voice of the person you are calling, a claim Aliph doesn’t make for the Jawbone. But, while voices sounded fine on the Plantronics, I couldn’t detect any difference between the two on that score.

Both gadgets are meant to be more stylish, and both will be available in multiple colors. But, while the Jawbone is just a smaller iteration of its original slab-like form, Plantronics has done something more radical with the Discovery 925: It has tried to make it look like jewelry. The Discovery’s electronics are housed in the diamond-shaped portion of the device that goes on the ear, and the microphone sits at the end of a long, V-shaped boom that is open in the center. Plantronics says the design is suitable for both genders, but admits it is a bit more aimed at women and at fashion-conscious men.

I believe some men wouldn’t feel comfortable wearing this new Plantronics model. It’s also longer than the Jawbone. But I did find it more comfortable to wear, since it doesn’t protrude as much into the ear.

The Plantronics claims longer talk time — five hours vs. four hours for the Jawbone, but the Jawbone claims longer standby time — eight days, vs. seven days for the Plantronics. The Jawbone weighs more, at 10 grams, compared with 8 grams for the Plantronics, but neither felt heavy on my ear.

I did prefer the Plantronics’ controls over the Jawbone’s. The former uses obvious buttons, while the latter employs unmarked, hidden buttons whose location you have to learn by touch.

Both of these earpieces do the job, but if you have to choose one, I’d pick the Jawbone.

• 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.

Corrections & Amplifications:

The Aliph Jawbone cellphone earpiece weighs 10 grams, and the Plantronics Discovery 925 earpiece weighs 8 grams. An earlier version of this column erroneously reported the products’ weights in ounces.

But what if you only have a standard cellphone with a lousy Web browser — or even the best Web-browsing phone, but it lacks a fast data connection? What if you’re speeding down the road in a car, where typing is dangerous?

Now, there’s a way to get your questions answered despite those hurdles. It’s a free cellphone service that lets you ask any question answerable via a Web search, using any cellphone, by simply making a voice call. It’s called ChaCha, and I’ve been testing it out.

To use ChaCha, you just dial 800-2chacha (800-224-2242) and state your question. In a few minutes, you’ll get an answer via text message. In one test, I asked ChaCha who was the winning pitcher in the previous night’s Red Sox victory against the Yankees. In a few minutes, I received a text message with the correct answer: Daisuke Matsuzaka.

ChaCha requires no registration and works on any cellphone carrier. It needs no special codes or key words. You just state your question as if you were asking a friend. If you prefer to type your question, you can text it to “ChaCha,” or 242242. Though ChaCha itself charges no fees, your phone carrier may charge for the minutes you use, or for the text messages.

The service works by routing your questions to one of 10,000 hired “guides” — students, stay-at-home parents, retirees and others — who look up the questions on the Web and reply. They get paid 20 cents per answer.

Naturally, these guides vary as to their speed and accuracy. If you don’t like the answers they give you, or you want related information, you can call back or reply to the text message with a follow-up question. For instance, after learning which pitcher had won for Boston, I asked who lost the game for New York. I was quickly informed it was Phil Hughes.

Overall, I liked ChaCha. In most cases, I received fast, accurate, useful answers. But it has two weaknesses. One is that the low-paid, part-time guides can provide inconsistent service. When I asked for the best Mexican restaurant in D.C., for example, ChaCha came up with a choice that few locals would cite.

The other is that, unlike many other cellphone information services, ChaCha doesn’t automatically know your location. So, unless you include a location in your query, it’s clueless about questions such as “Where’s the nearest drugstore?”

ChaCha is hardly the only information service for cellphones. Google offers a text-message service where you can ask questions on a wide variety of topics, and a voice-based service that locates businesses near your location. Microsoft’s TellMe subsidiary just introduced a voice-based service that answers location-specific questions about businesses, weather, traffic and movies, and displays the answers on the screens of BlackBerrys.

But these competitors are more limited than ChaCha in key respects. Google’s broader mobile-search service, Google SMS, requires that questions be sent via text message using special key words. Its voice service, Goog411, finds only local businesses. TellMe’s new service is limited to location-based information and works only on certain phones.

I tested ChaCha using three very different phones: a cheap, bare-bones Samsung flip phone from Sprint; a midrange Motorola Razr from Verizon; and an Apple iPhone running on AT&T. I asked questions via voice and text from various locations, including my car, where I used a hands-free microphone.

I asked about sports, TV shows, journalism, history, weather, nutrition, demographics and shopping. ChaCha handled most of these inquiries correctly and was able to fix most of its errors after I asked follow-up questions. For each question, it sends two text messages: one restating your query and saying it’s working on it, and the second containing the answer.

Each ChaCha answer is accompanied by a Web link. If your phone has a decent browser, you can go to that link to learn who the guide was, and what his or her Web-site source was.

ChaCha gave me the weekend weather forecast in Boston, the date of death of Abigail Adams and the cast of the TV show “Brothers & Sisters.” It provided Peyton Manning’s salary and the sodium content of a McDonald’s quarter pounder. Its most impressive performance came when it correctly answered an obscure historical question: “When was the Gaspee burned?” The Gaspee was a British tax-collection ship burned in Rhode Island in 1772 in what is often considered the first act of war of the American Revolution.

The company is working on adding automated location knowledge, at least on certain carriers and phones. For now, you can tell it your location by sending a special command via text message. But even without the location features, ChaCha is a fun and useful service.

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.

Corrections & Amplifications

ChaCha, a mobile-phone search service, is incompatible with several small U.S. cellphone carriers. This column incorrectly said that the service works on any cellphone carrier, based on incorrect information supplied by the company.

Yes, more cars are making it easy to connect wirelessly with Bluetooth-equipped cellphones so drivers can make hands-free phone calls — but not hands-free text messaging. And that results in the dangerous practice of texting while behind the wheel.

And, yes, you can pipe the sound from your portable music player into the car’s speakers. But you usually have to control the song selection and skipping by handling the player itself, and that’s another dangerous distraction.

Some car makers solve this music problem with integration kits that transfer control of the music player to the dashboard or steering-wheel controls and display song information on a dashboard screen. But this option is most common in luxury cars and is typically designed only for Apple’s iPods.

Now, Ford Motor, working with Microsoft, has come up with a system that’s a big step forward in integrating cellphones and portable music players into cars. It’s highly versatile and works with numerous devices on a wide range of Ford models.

I’ve been testing the $395 option, called SYNC, with multiple cellphones and music players. It’s quite good and indicates that the digitally backward auto industry finally may be getting it.

SYNC combines the often separate cellphone and music-player functions into one unified interface that can be controlled by a voice-recognition system that works well. You can command it by voice to play a single song out of thousands on your iPod or other music player. With some phones, it will even read your incoming cellphone text messages to you, and properly pronounce text-message shortcuts such as LOL (Laughing Out Loud.)

Ford isn’t limiting this system to luxury cars. It’s available on a dozen models — including the company’s least-expensive car, the Ford Focus. I tested SYNC on a Focus.

SYNC simultaneously handles multiple cellphones and music players from a variety of companies. It imports and remembers the address books and song information for up to 12 phones and four players, so that as you connect and reconnect a remembered device, wired or wirelessly, it is ready to go. It doesn’t have a hard disk and doesn’t store your music.

Unlike other approaches, the Ford system doesn’t require a special cable or proprietary connector. It uses a standard USB port and the cable that came with your player. SYNC will even play music directly from a USB thumb drive. There’s also an audio-in jack for players that don’t support USB, or which require both.

SYNC can even stream music wirelessly, over Bluetooth, from the cellphones that support this feature. However, due to limitations in Bluetooth, it doesn’t transfer song selection controls, or the song information display, to the dashboard in this scenario. The same limitation applies if your player can be connected only with the audio-in jack.

I tested SYNC with two music players and four cellphones and the system handled them all effortlessly. I used a year-old iPod and a new Samsung P2 as my test music players, and SYNC quickly transferred their song information and allowed me to select playlists, artists, albums, genres and individual songs by voice command.

I tried the cellphone functions with an Apple iPhone, a Motorola RAZR, a RIM BlackBerry and a new HTC Shadow phone and, again, all worked properly. While phone calls and address-book imports were handled easily on all the phones, some of SYNC’s advanced functions, like the reading of text messages and the streaming of music, aren’t widely supported on all phones. For example, only the RAZR worked with the text-message feature.

The iPhone test was especially interesting because it is both a Bluetooth-equipped phone and a full-fledged iPod. The SYNC treated it as both, simultaneously.

I found the voice-command system surprisingly reliable. In four days of testing, I encountered only a few instances in which my commands were misunderstood.

SYNC has some limitations. While it can read text messages on compatible phones, Ford didn’t build in the ability to dictate and send text messages. You can send only canned messages, like “Be there in 20 minutes.”

But there are a lot of advanced features — too many to list here. And Ford plans to add others, which owners will be able to install at home. Detailed information on the system is available at syncmyride.com.

Alas, I did discover one glitch. Twice during my testing, SYNC mistakenly declared that a music player had been unplugged when it hadn’t been. The system recovered with a little fiddling, but Ford needs to fix this.

Still, SYNC is a very well done method for integrating digital devices into a car, and in a model that most people can afford.

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 Chocolate can make and receive phone calls and text messages, but it’s designed as a music player first. In fact, it was crafted to look like an Apple iPod, right down to its most prominent feature, a navigation wheel. Verizon is heavily hyping the Chocolate, hoping to capture some of the same sort of buzz that catapulted the iPod, and later Motorola’s RAZR phone, into the status of cult-style accessories.

The Chocolate will hit Verizon stores next week and is available at Verizon’s site for $150.

While the Chocolate may look like an iPod, however, it doesn’t work like one. In fact, as a music player, it functions like an iPod designed by a committee. It’s burdened by a ham-handed user interface and other failings that would get its designers fired at Apple. As a result, the Chocolate, which I’ve been testing for a week or so, isn’t as good a music phone as, say, the Sony Ericsson Walkman phone.

The Chocolate is available now at Verizon’s Web site for $150, after a $50 rebate, with a two-year contract. It will reach Verizon’s stores next week. If you’re serious about using it for music, however, you’ll have to shell out an additional $100 for a 2-gigabyte memory card, which can hold about 500 songs in standard MP3 format. That’s because, incredibly, the Chocolate comes without a memory card, and has a pitiful 64 megabytes of internal memory for storing songs.

This phone is handsome. It’s a black slider design, small and light. Unless you slide it open, the phone keypad is hidden and all you see are the roomy screen, the navigation wheel and glowing red control indicators. It has a decent camera that can take still pictures and crude videos. Unlike an iPod, the Chocolate can play music through a built-in speaker, which sounded very good to my ears.

The best user interface elements on the Chocolate are two buttons on the right side, which take you directly to the music player and camera functions, so you don’t have to wade through menus. These buttons are called out by little labels at the right edge of the screen. But it’s downhill from there.

One big problem is that cool-looking wheel. It turns out that, unlike on the iPod, it isn’t a wheel at all — just a common five-way navigation pad made to look like an iPod wheel (in the popular European model of the Chocolate, it had a rectangular shape). While it is touch sensitive, like the iPod’s wheel, you can’t scroll with it by moving your finger across it in a circular motion. You have to press the buttons in the middle and at the corners.

Worse, the touch sensitivity is poor. While you can adjust how sensitive the wheel buttons are, I found them to be either so sensitive that it was easy to accidentally activate them, or so insensitive that you had to hit them twice — hard — to get things done.

In another bad design decision, the “end” button that terminates calls, turns the phone on and off, and gets you back to the home screen, has been moved from its traditional position across from the “send” button to the side of the phone. This requires a major adjustment and is awkward, because the button is very small.

The music application itself is pretty standard, but is full of unwelcome surprises. For instance, when you turn on the phone, you can’t start listening to music immediately if you store your songs on the memory card, because the player has to load the songs from the card each time. You can set the player to shuffle through your songs, but if you manually advance to the next tune, it goes in order, rather than picking a random song.

And the Chocolate doesn’t handle your MP3 files properly. I loaded the card with 208 very standard, unprotected MP3 files — files that are perfectly recognized on all computers, phones and portable devices I’ve tested. But the Chocolate failed to read the song information — artist, title, album — on all but a handful of them. So I could select them only by file name.

I had a similar problem with my personal photos. Of the 16 picture files I loaded onto the card — again, standard files I’ve used to test numerous devices — the Chocolate could display only four.

In fact, the Chocolate’s multimedia features are really designed mainly to encourage users to buy songs, pictures and videos from Verizon’s online download and streaming services — VCast and Get It Now — not to let you use your own content. The phone works much better with $2 songs you buy from VCast (twice what Apple charges) than with free songs you load onto it.

This is the opposite of Apple’s model. Its iTunes Music Store exists to sell iPods, and the iPod works perfectly with music from other sources, even if you never buy a song from Apple.

I do believe that, someday, the merger of the cellphone and the music player will result in a great device for consumers. But the Chocolate isn’t it.

• Email me at mossberg@wsj.com.