2 Feet 2Ft Audio Stereo cable male to male 3.5mm M-M 2' - eBay (item 290314025985 end time May-03-09 12:08:54 PDT)
This is an example of what you would use, your car stereo
head unit needs a standard headphone input, and this cable connects your zune to it so that you can play your zune's music through your car speakers.
It's the easiest way to play your zune's music in your car.. although i suggest getting a car charger for your zune also so that it doesn't run out of battery:
http://cgi.ebay.com/AV-CABLE-CAR-WAL...1|293:1|294:50
Ebay makes life so much easier