Well from what I can gather, As PC processors were getting faster with dual core etc etc, the Power PC processors in the G4's (or whatever the ones were prior to going to intel) were getting a bit outdated in speed terms compared to the new processors avialable on a PC platform, so apple put pressure on IBM to make a better RISC chips for the next gen Macs, but IBM were putting more research into Next Gen console (Xbox 360, PS3 etc) as it would generate them more money as they would be more demand for these than for Mac's, so they had a falling out over it as it wasnt in the best intrest of apple (as they would have to wait longer for a new chip to compete against PC chips).

So Apple went to intel (or visa versa) as there was a gap in the market for a new chip supplier for apple and as intel didnt have the rights to the power PC chip format they went with PC platform (think its X86) for the new mac's, with apple changing their opertating system to run on the X86 platform, hence why they can run windows too (via bootcamp), I even saw on the web a Dell laptop running Apple OSX (with some tinkering) so that basicly shows that they are the same now. You could say windows won as they supported X86 and apple went down the RISC route right at the start of the company, but then again Microsoft might be worried as Apple could release a version of OSX that can run on any PC and use PC software....

Only time will tell whats going to happen