@Pristine : no MS can't, the 360 is already basically free right now, the 'sweet spot' was already reached for the 360, any subsequent price cut would have little effect now, anybody who wants a 360 already has one now.
When Sony cuts the price, I see no reason the situation doesn't go back to what it was before MS price cut last september, with the PS3 outselling the 360 every week worldwide.