iTrip is an attachment for iPods that allows transmitting your iPod’s audio output to an FM receiver.
At first, I thought my iTrip was broken, but I realized I had only forgotten how to set it to a certain frequency. One must play the particular frequency file on the iPod (with iTrip attached of course) until the iTrip begins to flash. Once it flashes, hit pause. Then it’s set and ready to go.
It’s still not perfect. It’s best to use it with another power source in your vehicle, as it will drain the iPod battery in no time. And on days when FM propagation is active, you may have to change to other frequencies. Remember, the quality is going to be no better than FM radio stereo reception, which isn’t all that bad really. If you’re a big audiophile, go with a wired connection option for your vehicle.