Xbox 360 will continue to lose grounds to PS3. Both will continue to grow, but the PS3 will grow at a faster rate.
However, the install base of PS3 will not overtake Xbox 360 in 2010. It will happen in late 2011 or 2012.
Just when PS3 begins to overtake Xbox 360 in 2011/2012, Microsoft will release the next console. The new Xbox console will likely has some serious quality problem like the 360 did with RROD -- but it won't bother Microsoft because Microsoft knows that they can get away with selling defective products (it's a Microsoft's tradition) and customers will just have to put up with it.