[monkeyboy]

You'll need the 3.5mm adapter that esanto mentioned. Then there are two common ways to get the signal into your car stereo if it doesn't have an AUX input: 1) FM transmitter, or 2) cassette input. FM transmitter is a bit easier to deal with but I've found the quality of the signal is often better with the cassette input. You can buy either on ebay, and in some consumer electronics stores (try Radio Shack, Bestbuy, etc). On ebay, search for "car audio cassette adapter", or "fm transmitter adapter".

Oh, one advantage of the cassette method is that it requires no external power. The FM transmitters require power, either battery or often plugging into the car lighter jack (which then makes it impossible to use it for something else, like your GPS or cell phone charger)...