The iTrip is that FM transmitter for ipods right? afaik, you plug it into the top and then it transmits an fm signal that your car or whatever can pickup.
I've heard that they way you set it up is a little bit interesting. You transfer over a song from the included cd and that song is actually an FM frequency. You then play that song on your ipod, with the itrip in it, and then the itrip picks that up and begins transmitting along that frequency.
Seems pretty cool, but Im not a huge fan of fm transmitters.
-GB