The
VMWare player is a free application you can download to use preconfigured virtual machines.
These are being provided more and more for evaluation purposes, but a more interesting use is the browser applicance. It's a pretty simple concept, and will appeal to anyone who's tried to set Windows XP up to run in least priviledge mode.
Virtual Machine
The Browser Appliance enables you to safely browse the Internet from within a VMware virtual machine -- protecting your host PC from spyware and malware.