I just bought an itrip from the apple store for my wife and it works awesome. you just set the radio station on the ipod and then use the one for your truck that is not being used and it is CD quality.
Nonsense. Griffin describes the sound quality of their product as follows:
"What is the quality of the audio when played through the iTrip! Is it better than FM?
Simply put, FM radio is not the best quality audio in the world. It lacks some high and low frequencies, it has a fairly poor signal-to-noise ratio and it is no where near CD quality. The iTrip simply creates a mini FM radio station on top of your iPod, therefore it will never sound any better that the best FM radio station you've ever heard.
However, it still sounds pretty good. With a clear frequency the iTrip will deliver your iPods music at a surprisingly clear and high level of quality. And unless you have an AUX input or cassette adapter - it's the ONLY way to play your iPod in your car. As far as comparing the iTrip to 'other' FM transmitters, the iTrip's sound quality will win every time."
Conclusion: If you have an aux jack, don't use an Itrip.