Quoting from About Virtualization blog:
During a preview of the upcoming Virtual Server Service Pack 1 by Jeff Woolsey, Program Manager for the Virtual Machine Technology Group, Microsoft revealed that it will provide official support for Linux under Virtual Server.
While showing off Red Hat Linux running as a virtual machine during Steve Ballmer?s keynote at the Microsoft Management Summit, Ballmer interrupted:
?As much as that hurts my eyes, I know that?s an important capability for the virtual server technology for our customers.?
Microsoft will also support Linux in the surrounding ecosystem providing management and monitoring support in the MOM management pack.
Developed by Vintela, MOM will also support standard Linux system, Mac OS, and UNIX systems like AIX, HP-UX and Solaris. With the continued cooperation between Sun and Microsoft, support for Solaris under Virtual Server might be a possibility. McNealy and Ballmer will meet shortly to discuss interoperability efforts, perhaps even Solaris running under windows.