Try this one. http://chevyavalanchefanclub.com/cafcna/index.php/topic,137781.msg2010549.html#msg2010549.
Here's the unit I went with in my 08. http://www.pioneerelectronics.com/PUSA/Car/DVD-Receivers/AVH-X5500BHS
I love this thing. It syncs up with my iPhone within 5 seconds and streams itunes radion, pandora, or my music on my phone. It also has a direct Pandora sync. I have an $80 Garmin with free lifetime street updates so I didn't need a unit with nav built in. My unit cost about $350 and I bought it on ebay. Good luck to you on whatever you choose.