Depending upon what version you are looking for it might depend upon the area. I live in Rockville Maryland and the last time I went out I didn't even see a 40 gig out on the shelves. At the same time when I was in pittsburgh last week they seemed to be everywhere including the MGS4 80gig bundle.
I guess call ahead to places like Walmart, Target, Best Buy, Circuit City, and any other large chain store to see if they have them in stock. At least on a few of those stores websites you can check to see if a store near you has it. But from my experience with games at least, what it says online about a store having ir or not wont always be accurate. If you go with Circuit City you can buy it online and do a store pickup.