This isnt mine, but a freind from another board. Check out the auction, and you will get the gist of what it is..
http://cgi.ebay.com/ebaymotors/do-it-yourself-GM-Delco-Auxiliary-aux-input-ipod-mp3_W0QQitemZ320079398116QQihZ011QQcategoryZ38636QQssPageNameZWDVWQQrdZ1QQcmdZViewItem (http://cgi.ebay.com/ebaymotors/do-it-yourself-GM-Delco-Auxiliary-aux-input-ipod-mp3_W0QQitemZ320079398116QQihZ011QQcategoryZ38636QQssPageNameZWDVWQQrdZ1QQcmdZViewItem)