Firstly I would like to know if any companies sell car docks that you just snap your phone into and it transfers the sound through your speakers. I've tried searching but I really don't know what something of the sort would be called (Car dock?).....this would be much easier than option two as described below:

Currently in my car I have a Pioneer headunit...I have an adapter that has a male headphone jack coming out of it which I use to listen to my mp3 player or to hear the directions from Streets and Trips off of the laptop better. Is there a way that the headphone jack could be adapted to plug into the little headset hole on the side of my Sanyo PM-8200? I know it seems a bit half-assed, but if anyone thinks it could work please let me know.