I have a 2004 SUV, before they started building MP3 compatibility into the car stereos. I've been able to listen to my iPhone music library over my factory car stereo by trying different products that use the radio frequency. Best Buy carries them, and also carries the line out adapter that fits into the iPhone headphone jack. Some didn't work at all, and I was able to return them for a refund, saying they were defective and didn't work. One worked for awhile then quit working. I'm having success with a new one, but the sound has radio hiss. I'm going to try different radio frequencies (generally 4 are offered, like 88.1 FM,) and see how that works. At least it's something. Before going to Best Buy though, ask your dealer if it's possible to install a cable in the back of the stereo for your MP3 player, and ask a car stereo shop if they have any options, like changing out the stereo for a new one. Sometimes a dealer will give you a rote "no" when there's a jack for it on the back of the stereo. If you can get to the back of the car stereo and look, do it. You might be able to hook in a simple cable from Radio Shack into the line in jack on your car stereo, and if you buy a line out adapter for the iPhone, you're set. We use the same idea to listen to music on work computers (hook into line in or mic jack on the PC).