I have an auxillary connection that will hook up any iPod / MP3 Player with a head phone output. This includes the connection to the aux port in the back of the radio and the connection from that into the head phone jack to your MP3 player. I've attached a picture of what is included and another picture to show where it connects to the back of the stock head unit.
$35 shipped. Brand new these things are $90 + shipping from http://mp3yourcar.com