The wire harness you'll need is less than 10 bucks at most Walmart stores that I've been to. With the harness, it's simply a matter of color coding and splicing! Also, don't forget your dash kit to fit the new sized head unit if you haven't already bought one! Here's a link to a thread I made with the wire colors if you need it:
http://www.automotiveforums.com/vbul...d.php?t=673256