Is there a practical way to add bluetooth to the factory sound/navigation system ?

Can the entire head unit on a 2006 or 2007 with bluetooth be utilized?

 

Im interested in the same response, recently purchased an 05 CTS with Onstar, but really don't want to purchase talk minutes through them. Especially now that so many vehicles are BlutTooth capable. Is there a way to either add it aftermarket or perhaps replace with a newer audio system fro say on 07 or 08 that would allow me to link cell through audio system?