The SCVMM 2012 beta was announced at MMS. Go pick it up here: http://www.microsoft.com/downloads/en/details.aspx?FamilyID=e0fbb298-8f02-47e7-88be-0614bc44ee32
Now, I will warn you. This is a big update. Not just some little incremental update. It includes some new ways of thinking about your data center. And it includes a lot of “cloud” type words and ways of thinking.
I consider this update a paradigm shift in the VMM world. A big change in thinking, automation, abstraction, packaging, and delivering.
It also includes support for managing XenServer. This is a feature that is near and dear to me. There is a supplimental pack that is required for your XenServers which can be obtained from here: http://www.citrix.com/xenserver/microsoft-beta
This gives the ability to deploy too and manage XenServer. You still need to setup your environment using xe or XenCenter (no different than Hyper-V) – but you can control and manage VMs with SCVMM.
Other MSFT folks have mentioned the other big paradigm changes, so I won’t cover them here. http://blogs.technet.com/b/scvmm/archive/2011/03/22/system-center-virtual-machine-2012-beta-available-now.aspx