This is a lot of fun and (hopefully) will explode into more fun:
Microsoft e-mails suggest priority was 'to help Intel'
Essentially, Microsoft agreed to help Intel by marketing Vista as being "capable" of running on Intel's low-end 915 graphics chip, letting Intel push out their surplus of motherboards and improve their earnings.
The article doesn't call marketing with inaccurate claims, which are known internally to be inaccurate, for the financial benefit of another company, lying and collusion, but er, it is. I say so.
The WSJ has a good article as well, but it's a $$ thing, so read it if you can.