you could get an RF modulator off of ebay and do the trick for little money. taps into the antenna input, then you tune into a certain station, the quality isn't perfect but you're listening to mp3s on a stock deck so it won't matter.


http://cgi.ebay.com/ws/eBayISAPI.dll...category=18798

http://cgi.ebay.com/ws/eBayISAPI.dll...category=32826