I thought I'd share this with everyone since it's definitely useful and serves a dual purpose. I currently use the TomTom ONE 3rd edition GPS device, but the higher model, the TomTom GO 930, which was recently released, has an FM transmitter. This is a cool feature for those of you with MP3 players, but don't have an auxiliary input on your current car stereo to support your MP3 device. So instead of upgrading to a completely new head unit to support MP3 connectivity, you simply hook up your MP3 player to the TomTom GO 930 and you can tune your car stereo's radio to pick up the signal on your FM transmitter. Tada! Instant MP3 player playback through the GPS without the hassle of getting a new stereo or auxiliary input.