While its not impossible I don't think it will likely pass the 360 by 2011. The price cut will be huge for the ps3 if it gets a 100 dollar cut. I think we'll see that by the end of 09. PS3 will get a big surge through the first half of 2010 then slow down to the point where both 360 and ps3 sell at almost the exact same level again. Personally I'm not sure who will win between the two but I don't see either finishing with anything more than say....a 5 million unit lead over the other.
Thats my opinion though with the crazy stuff thats happened this gen I could be completley wrong.