If you are what Microsoft terms as a "Most Valued Professional" (MVP) then you should be able to get access to the Windows source code now.

"The Redmond, Wash., company said on Monday that all the MVPs within the Microsoft platforms community and living within the 27 eligible countries worldwide will now be able to access Windows source code at no cost."

The program covers "Microsoft Windows 2000, Windows XP, Windows Server 2003 and future versions of Windows operating systems, including all released versions, service packs, betas and subsequent releases." Nice to see them giving something back to the computing community like this.