I would like to point out a few facts. Facts, people. Verifiable facts, straight from the honchos at OLPC themselves.
1. Microsoft committed to purchase 10,000 machines in May, customized to run Windows. They're free to do whatever they want with those machines. For instance: if Microsoft wants to run a pilot of unspecified size in two towns, and turn that pilot into a huge PR event... they are perfectly free to do that.
2. The reason these 10,000 systems had to be customized? Simple: Windows can't even boot on open firmware. Can't even boot! Which means that the other 990,000 XO (or so) systems in the wild CANNOT EVEN RUN WINDOWS with the firmware installed on them.
3. OLPC builds XOs with Linux. OLPC will continue to build XOs with Linux. OLPC has no plans to change this. None.