Virtual Server - a virtual machine solution for Windows Server 2003 that "spans development, test and production environments, and delivers improved hardware efficiency and increased productivity for administrators and developers as it will be far easier to deploy and manager these machines in that environment." The package targets production environments, including those customers who want to migrate their legacy business applications, which could be currently running on Windows 2000 or NT 4.0. Virtual Server will also allow customers to run multiple operating systems concurrently on a single x86 hardware server, including Linux and Unix-based operating systems.
Available here. Article here.