If you’re interested in open source virtualization, I’ve composed a brief list of websites which could be worth checking out.
A feature comparison of various virtualization platforms. (Including also some proprietary software):
A blog post about KVM vs. Xen. More of a pro-KVM speech from a Linux activist point of view:
Another article about KVM vs. Xen. More constructive this time:
A comparison of Bare-metal, KVM and Xen:
An article about Xen vs. OpenVZ. (A few years old. Written in 2007):
If you know good articles, blogs or forum discussions on the topic, please comment and share.