Holy thread archaeology batman! Dug this one up from the past, didn't we?
Figure out your backspacing, then go look around. You need at least a 16" wheel to clear the front brake calipers and a 4" centerhole width to clear the front hub assembly. Your factory wheels are 7" wide so that would be a good starting point. Bolt pattern is 5x5.5". You should have at least 4" of backspacing unless you want the tires to stick out from under the truck a lot. I don't like that as you end up with a lot of crap thrown up onto the sides of the truck as soon as it rains.