I can confirm this is the case at my local store in Florida.

Just got back from my Walmart. 360 version had sticker price of 39.96, and rang up at that price sure enough. Didn't check on the PS3 version.

I wonder how long this will last before the price gets changed in the system to $59.96 and the Wal-mart stores get a memo to re-sticker their old $39.96 stickers.

Thanks for the heads-up OP!