You can get a Parrot Hands Free kit or a Nokia one that you can connect up to your stereo and speaker system...they are pretty decent, but they dont charge your phone, they are soley hands free kits, otherwise, you can now get Stereo head units that have Bluetooth built in with a mic, so when you get in the car, just pair it up and it even copies your phone book, so it will show you whos calling on the stereo display, then the conversation will go through the stereo....
Hope that helps.
Nilz