By Roger A. Grimes (InfoWorld)
I've been at several recent conferences where virtual machine (VM) and security “experts” were telling audiences how VM technology can be used to improve computer security. Wow! They are either drunk on the marketing Kool-Aid, misinformed, or simply trying to misrepresent VM capabilities to sell more product.
VM technologies are very cool, and great at saving money (and space, electricity, and more), but in all but a small minority of cases, they will not improve your overall security posture.

http://weblog.infoworld.com/securityadviser/archives/2008/04/virtual_machine.html