Microsoft is planning to launch 'hypervisor' software for servers to run multiple operating systems. Bob Muglia, senior vice president in the Windows Server Division, said the hypervisor software will be be a built-in part of Windows. It will allow companies to virtualize multiple operating systems.
Such software lets multiple operating systems run on the same computer, a feature that's useful for extracting as much work as possible from a single system.
The hypervisor software is planned to become available near the debut of Longhorn Server in 2007. More details at CNET