I’ve started playing with a new virtualization alternative, Virtual Box (http://www.virtualbox.org/ ). It’s an open source alternative to other virtual machine programs like VMWare or Microsoft’s Virtual PC. It runs on both Windows and several flavors of Linux, and has guest additions for Windows and Linux. It also has USB support, a feature lacking in Microsoft’s product.
I found the user interface very intuitive. Simply clicking New brings up a wizard and walks you through the steps to setup a new machine.
You can choose to use a physical CD/DVD or mount one off of an ISO file, access hard disk info, audio, etc all by clicking on the blue links you see above.
As an initial test I downloaded Damn Small Linux (http://www.damnsmalllinux.org/ ) as a ISO file, and ran it in “Live” version as a mounted image. I only gave it a quick run, but so far it seems to work OK. I plan further testing with XP as a test image, but would be interested in seeing comments with your experiences.
Arcane Code 
Been using the Virtual Machine for several months now. The application is great, expect I can’t seem to enable the full screen and drag and drap features, even though I have installed the add-on.
Been using Virtual Box for about 30-45 minutes now with XP as host and Ubuntu 7.10 Desktop Edition as the actual virtual OS. Been great, don’t have a clue if I’m connected to our house network or some wierdo limbo network (its a wired connection). Since its wired i guess its ours, but i dont know the ip’s are all wierd, but i can get on the internet and do all sorts of stuff, so…
oh yeah, everything else is great not sure if sound works, havent tried yet, will look into that and let u know if it works