In the rest of the world excluding US, the PS3 will definitely outsell the XBox360 from now until Christmas because the sales are so close already in those areas.
I'm not quite sure that in America that it's a done deal that PS3 will outsell the XBox360. The general public are completely unaware of PS3 slim. The general public are still gonna be swayed by the new Halo ODST coming out with the reduced price on the Xbox360 Elite.
I'm a very pro-PS3 person. Talking to most people (non video game fanatics), most still see the Xbox as the better choice and the general public still go with the herd.