get a "Connects2" box off ebay, there are a couple of different ones depending what you want, I have one with USB, SD, and Aux, it plugs into the CD changer port of my single din concert. Its one of the best things I ever did to my car, it currently has an SD card in with 540 songs on it, and sits in the cubby under the climate control unit with the harness running up the back to the CD player