Slashdot had an article today pointing out that Virtual Box has made their project GPL OSS. This makes one of the first completely open source desktop virtualization solutions. I have been a fan of vmware, even though they are only partially open source, and their workstation product is rather expensive. I hav used Xen, but issues with display drivers make it difficult to use as desktop virtualization (though nvidia has said they will support it “some time in the future”).