I purchased the following from amazon.com: GOgroove Flexsmart X2 Advanced Wireless In-Car Bluetooth FM Transmitter with Charging, Music Control and Hands-Free Calling Capability for Android, iPhone, Blackberry and Windows Smartphones
This unit has streaming blue tooth audio from your phone and sends the music to the radio. It selects a quiet channel automatically to transmit on. You can pause and skip songs on pandora for example and can play songs stored on the i-phone. It was $59.99 and works great. It plugs into the cigarette lighter for its own power and has a usb output jack so you can charge the phone at the same time.
It really works great and doesn't get in the way, try this link to amazon.com:
http://www.amazon.com/Transmitter-Hands-Free-Capability-Blackberry-Smartphones/dp/B003PPGOC0/ref=sr_1_1?ie=UTF8&qid=1302757273&sr=8-1
thanks...brian