If you want to find out more about the underlying processor enhancements from Intel and AMD that will support and be required by Windows Server virtualization, check out the following sources:
See http://www.intel.com/technology/virtualization/index.htm for information concerning Intel VT technology
See http://www.amd.com/us-en/Processors/ProductInformation/0,,30_118_8826_14287,00.html for information about AMD-V technology
For information on how Microsoft and XenSource are collaborating to support running Linux on Windows Server 2008, read the following article on Microsoft PressPass: http://www.microsoft.com/presspass/press/2006/jul06/07-17MSXenSourcePR.mspx.
The starting point for finding out more about current (and future) Microsoft ...