According to FiringSquad, the new Xbox technologies will be based on the latest in IBM's family of state-of-the-art processors.
The next version of Xbox is expected to be announced in January by Microsoft founder and Chairman Bill Gates and to be on sale next fall ahead of the holidays, according to Doherty. So Xbox 2 will have an IBM CPU and an ATI VPU... just like GameCube! Just thought I'd add this link to EETimes which goes over the chipset a little more.