OWC used to make a great product for the iPhone... It was a cable, one end was a dock connector, the other end split into a USB and audio out. Perfect for my wife's car which has an outlet (which the USB can charge the iPhone with any cheap outlet -> USB device), and an Audio in for playing music from the iPhone.
My wife is rough in the car, shuttling around 3 kids, the USB end got broken. She can still play music through the thing, just can't charge via the USB. OWC used to make one (that's where I got mine), but they don't make it any more.
Anyone seen these other places, I can't seem to find them.
Thanks