In case you missed it Sun Oracle Virtual Box 4.0 has been released. We here at Linuxinstall.net have been a huge fan for sometime. Brian even uses it to host a firewall. The 3.x stream of development has been stable and easy to use. We are doing some long term tests and will probably be releasing a review of some of the top virtualization options later this year. We found a nice first look to hold you over until then over at linux-mag.com. Ken Hess gives a quick run down and concludes that you will want to give it a try but you should probably wait to put it in production until later this spring when they have some of the remaining bugs worked out. It's a short article and a good read so go check it out.