First off, never take any move by Apple on face value. Every move is laying the groundwork for something down the road. iTunes was a means to an end, the Mac Mini is laying the groundwork for something down the road. Every move, every product is a piece of a whole.
http://www.pbs.org/cringely/pulpit/pulpit20050609.htmlMicrosoft 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.
Enter Apple. This isn't a story about Intel gaining another three percent market share at the expense of IBM, it is about Intel taking back control of the desktop from Microsoft.
Intel is fed up with Microsoft. Microsoft has no innovation that drives what Intel must have, which is a use for more processing power. And when they did have one with the Xbox, they went elsewhere.