I’m guessing that this new Satechi Bluetooth FM Transmitter which can accept AD2P Bluetooth music from your mobile phone and transmit it to your car stereo via FM will get really popular now that more and more handsets come with MP3 players as standard. The fact that you get echo cancelled handsfree via an internal mic, plus a Line In socket for iPods etc is just a bonus really. Not cheap though at $99.00.
Bluetooth Hands-Free Transmitter provides a live full duplex communication solution using Bluetooth technology through FM transmission to your FM car radio and allows you to speak to callers through a built-in DSP microphone (it turns your car stereo to Giant Bluetooth Headset). This is accomplished without the use of external wires and without the hassle or expense of custom installation. The device is pairable with any phone equipped with Bluetooth functionality or a connection to a Bluetooth adaptor. Device is AD2P compatible and will transfer MP3 Music using AD2P.