I have an '06 GMC Sierra 1/2 ton 2wd reg cab, short bed. The wheels are 6 lug and yes its a 2wd.
I have found a few sets of '01-05 Yukon/Denali wheels. Example (http://seattle.craigslist.org/est/pts/179062085.html)
Can anyone tell me if these will fit me truck? I've asked Les Schwab and the GMC dealer but no one can tell me for sure. They all say to try them out is the only way, which I will do, but it might make a transaction difficult as I will have to drive a little way to get these.
Any help is appreciated. Thanks!

they should fit with no problem

They bolt right on. Should look cool too!

Well they're on.
Looks a lot better than the steel wheels I think.
Next up, 4" in the back/2" in the front.

looks good