Noticed it is back in stock on best buys website and on that other website the 250gb ones say in stock again.
So while i agree that there is a stock shortage i don't think it is a proper shortage ala Wii or how the 360 was a couple years back. Because they were sold out everywhere ven online. If it was as bad as some make out then they would not be available on the internet either, not as widespread as it appears at least.
As others have mentioned i think it is obvious Sony are saying that to try and drum up more interest in it because sales have started to drop a bit as also pointed out. If i remember right they dropped around 50% since the 1st week of the year?
So as i said i agree there are shortages in actual stores, but that is not because there are none to put on those shelves as they are yet to be made etc.. It is down to trying to use a tactic to keep interest going ala Nintendo style.