I'll admit I just assumed we didn't have a forum for Virtualization hosted on Microsoft.com, but actually the Technet guys do (thanks!).
So if you're as surprised as me and are interested, head over to the Windows Server Virtualization forum.
There is also a Windows Server "Longhorn" forum as well (of which virtualization is an sub-section).
Other sub-sections include:
Directory services, File and Storage, Migration, Management, NAP, Networking, Print, Setup & Deployment, TS, Security, Server Code and Failover clustering.