I blogged about the actual announcement of this a while ago and now Windows Server 2008 R2 is ready for download. As mentioned before Windows Server 2008 R2 is the next version of the Windows Server OS. This includes all the cool new Hyper V features. Hyper-V in Windows Server 2008 R2 includes three core areas of improvement for creating dynamic virtual data centers.
Check out the following resources for more info: