This morning I drove by Walmart, Target and Best Buy.
The most interesting was Best Buy since they seem to keep most of their stock in the front. I have never seen such a huge pile of PS3s or any console in my life. I estimated there must have been at least 150 units available. They seemed to be most 40gb models. The 360 had a similar pile, but much smaller, about 40 units with about 10 being arcades. Wii of course was nowhere to be seen. Lots of PSP in their various bundles, maybe about 40 total. DS was dwindling, only 5 left. I saw two people purchase them while I was there for about 5 minutes.
With Target and WalMart it's impossible to tell how many units they have. The display cases only allow for a max of maybe 10 boxes. There seemed to be plenty of 360s, PSPs and PS3s in the cases. There were no Wii's but surprisingly there were no DS's either.
I'm interested to hear what others have observed. I'm a little worried that DS may be in low supply and it's numbers could be down, but who knows how much restocking is occuring.