Microsoft Virtual Server 2005 R2 Product Overview

Virtual Server 2005 R2, now available as a free download, is the server virtualization technology engineered for the Windows Server System platform. As a key part of any server consolidation strategy, Virtual Server increases hardware utilization and enables IT staff to rapidly configure and deploy new servers. more..

VMware Server—a free virtualization product for Windows and Linux servers

VMware believes that the benefits of server virtualization should be universally available. Period. VMware has introduced free VMware Server Beta for immediate download. more..

erm.. a very good FREE solution for cheap multi-server deployment ;)

p/s: want to make my laptop vitrual too!