Check out PCMforless.com for your tune. Or if you have a 2006, I can do it for you for the price of the HPT credits. If you are using the 4L60E there is virtually no cleanup of the harness. Run the pink wires to ignition, black to ground, and hook up a fuel pump.
I have a pretty well documented swap here:
http://forums.trailvoy.com/showthread.php?t=51636
