I'm a big fan of virtualization, mostly because if configured correctly it provides an easy way to make better use of your system resources and, for a heavy tester like me, it provides an excellent way to run and test multiple operating systems, applications and environments without requiring lots of hardware.

From a business perspective, virtualization can be a licensing nightmare. It can also be prohibitively expensive. Although Microsoft's Virtual PC software will work on servers, the Virtual Server product is a much better solution.

Now Microsoft have changed their licensing model. Providing you are virtualizing Windows servers, from Windows Server 2003 R2 you can run up to four virtual servers for free.