I think summer 2012. Due to Sony's low profit margins on the Playstation 3 at the moment they will cut price when they 'need' to, not when they want a bit of red to brighten up the balance books.
To put it in perspective, in order the drop the price on 10 million PS3s by $50 they have to sacrifice half a billion dollars. This is something they will probably do in order to justify the brands continued existence for the sake of profiting in the future, but they aren't going to burn billions when their profits are so slim and it's not necessary to do.
Edit: Also they are selling the NGP for a loss this holiday/early next year. I don't even want to think about how much they will be bleeding this holiday if they had a price cut on the PS3.







