Some interesting bits (this has no basis in fact but is a good read nonetheless):
http://www.pbs.org/cringely/pulpit/pulpit20050609.html
People "in the know" love this idea, that Hollywood moguls are forcing Apple to switch to Intel because Intel processors have built-in DRM features that will keep us from pirating music and movies. Yes, Intel processors have such features, based primarily on the idea of a CPU ID that we all hated when it was announced years ago so Intel just stopped talking about it. The CPU ID is still in there, of course, and could be used to tie certain content to the specific chip in your computer.
But there are two problems with this argument. First, Apple is already in the music and video distribution businesses without this feature, which wouldn't be available across the whole product line for another two years and wouldn't be available across 90 percent of the installed base for probably another six years. Second, though nobody has ever mentioned it, I'm fairly sure that the PowerPC, too, has an individual CPU ID. Every high end microprocessor does, just as every network device has its unique MAC address.
So while DRM is nice, it probably isn't a driving force in this decision.
The vaunted Intel roadmap is nice, but no nicer than the AMD roadmap, and nothing that IBM couldn't have matched. If Apple was willing to consider a processor switch, moving to the Cell Processor would have made much more sense than going to Intel or AMD, so I simply have to conclude that technology has nothing at all to do with this decision. This is simply about business -- BIG business.
Microsoft comes into this because Intel hates Microsoft. It hasn't always been that way, but in recent years Microsoft has abused its relationship with Intel and used AMD as a cudgel against Intel. Even worse, from Intel's standpoint Microsoft doesn't work hard enough to challenge its hardware. For Intel to keep growing, people have to replace their PCs more often and Microsoft's bloatware strategy just isn't making that happen, especially if they keep delaying Longhorn.
http://www.pbs.org/cringely/pulpit/pulpit20050609.html