For those of us who commute by car, the big frustration about MP3 players is that there's no practical way to listen to your music. Most states have laws that preclude wearing headphones while driving. If your car has a cassette deck, you can hook up your MP3 player to the sound system with a cassette adapter for about $20. But most new cars come with CD players, not cassette decks.
That leaves FM modulators, which plug into the headset jack of your MP3 player and broadcast the music wirelessly to an unused FM channel on the car radio. At least that's what's supposed to happen. I've tried five of these gadgets in recent weeks. Sometimes they work fine. Sometimes -- depending on where you drive, the FM channel you pick, the geometry of your car, and the location of its antenna -- reception can get pretty sporadic. Still, these gadgets are worth a try.
Here are the best of the lot. Griffin's iTrip ($35) draws its power from -- and only works with -- the iPod. The beauty of it is you can set it to any station on the FM band. Likewise, Belkin's TuneCast II ($50) scans the entire FM range. The irock! Beamit ($30) only works on four FM channels. These last two modulators operate on AAA batteries for about 10 hours but come with power cords that plug into a car's lighter socket. Someday, all this will be built into MP3 players and car stereos. Until then, try these. If one doesn't work in your car, return it and try another.