Early this morning (NZ Time) we declared Release Candidate (RC0) of Windows Server 2008. As announced here: http://www.microsoft.com/presspass/features/2007/sep07/09-24windowserverrc0.mspx it is now available for download!
Go grab the ISOs (or soon the VHDs) from here: http://www.microsoft.com/Windowsserver2008/audsel.mspx)
If you're coming to the Christchurch TechNet Unplugged event later this week, you'll see it demoed then.
This release includes the Windows Server virtualisation Community Technology Preview (CTP) Because its a CTP, not everything is supported - its a preview after all, checkout Ben's blog for more info on the features that aren't supported/not present (yet) Also John has more info on how to install the Windows Server virtualisation (WSv) role
There's also a Channel9 video discussing the new features at http://channel9.msdn.com/Showpost.aspx?postid=343783
Windows Server 2008 home page Microsoft Virtualisation home page