Answering one question at the end of his keynote at the MVP Summit 2008, Ray Ozzie, Chief Architect at Microsoft, said that virtualization is absolutely fundamental in the company vision.
He also added that customers will see aggressive investments in the this area.
In particular Ozzie mentioned the OS virtualization approach offered by Parallels, saying that Microsoft is working to provide additional tools for server and desktop virtualization.
Update: Gus Pinto, the Microsoft MVP (and Citrix Evangelist) that submitted the question, published on his blog the whole transcript of Q&A about virtualization.