It'll be a week or two more before we can say for sure, but I think the PS3 is going to continue outselling the 360 by at least 10 or 20%.
Until the 360 gets a price cut of course. PS3 sales were at a catastrophic level before the 40GB model brought it back to life, so it'll be very interesting to see what even a cut of 50 will do to the 360.