To play music on your car speakers all you need is an audio input jack (for MP3/ipod) on your car and you can hook up the eDGe via a wire from the headphones jack.

My 2002 Mercedes oddly enough only has a CASSETTE player, so I stuck one of those tape-to-cd connectors into the cassette slot and the other end plugs right into my ipod/iphone and yes my Entourage Edge too