I have a used Seidio G4100M for Treo 650 which has an aux line out which allows you to play music and phone calls over your car's stereo, assuming it has a aux in. Alternativelly, if you have a car with a cassette player, you can use a cassette adapter. Great product, used but in very good condition.

I'm in the UK but very willing to ship worldwide. I'm looking for 15 (US$30) pluse 5 (US$10) shipping. Item is in very good condition and comes with all the Seidio parts in its original box.