A few months ago I stumbled across Moka5. Moka5 is more or less nothing else than a nice frontend for the free version of vmware’s player and creator. Now you may ask “Why use 3rd party software when I could use the stuff from vmware?”. Good question, simple answer: moka5 is comfortable. It brings along a lot of functions that make working with vmware more comfortable. Import existing vmware images from the moka5 lab oder vmware’s virtual appliance marketplace. Make your own vmware session with a few mouseclicks. Package together your vmware to have a backup. Install moka5 on a usb stick/drive and take your virtual pc with you; moka5 will install the necessary vmware software on the host pc, and deinstall it when you are done. Right now I have a few images on my moka5 usb drive that I carry around with me. Ubuntu, Backtrack, a Windows installation for trying out software without it mucking up my system.
Definatly something to have a look at if you are on the search for a free and easy to use virtualization solution.