Kindly Note: Do this at your own risk, Chances are that, you could spoil you Ipod and your Car Audio.
How you can make your car Audio, Ipod Enabled, I have a Pioneer Car Audio and Ipod Mini. You need Audio cables and stereo 2 mono pin.
Step 1: Check Whether Your Car Audio Has AUX
Before you start this experiment check whether you Audio system support AUX, I have a Pioneer CD Player which supports AUX