When I tune the iTrip, I only hear silence on the radio!
Sometimes the iPod has trouble communicating with third party devices, but we can fix that with a "soft reset."
First, make sure you have the latest version of iTunes on your computer and make sure that your iPod is fully updated. Then, with the iTrip plugged into the iPod and the iPod turned on, hold down the “Menu” and “Select” buttons until the Apple logo appears on the screen. If you have an iPod touch or an iPhone, perform the steps above while holding down the Home and Sleep/wake buttons. Then you can let go of the buttons and wait for the iPod to restart. After it restarts, try playing a song and see if the iTrip performs correctly.