Ever since I've gotten my 3Gs, I've been looking for a solution so I can listen to music through my car stereo. I didn't want to go the FM transmitter route. My GMC Denali stock radio does not have an AUX input and I didn't want to spend $150 on the product my local stereo store suggested. So I sopped by Radio Shack (actually looking for something else) and saw the cassette adapter. This thing works great. I can even listen to Pandora through the stereo. It might not be the slickest setup because you see the wire, but it works great for listening to music.