Windows 2008 R2 Migration Utilities for Hyper-V

Windows 2008 R2 Migration utilities has been updated with support for Hyper-V. Now it's possible to migrate your Hyper-V setup including VMs,Virtual Switches,VMQ,Chimney Settings etc.. to a Windows 2008 R2 host. The support is from :

Windows 2008 x64 Full Only
Windows 2008 R2 x64 Core or Full Edition to :

Windows 2008 R2 x64 Core or Full Editions. Also from documentation the scenarios that are not supported are  :

• The saved state of a virtual machine under one of the following conditions:
  
  • When moving from Hyper-V in Windows Server 2008 to Hyper-V in Windows Server 2008 R2.
  • When moving between physical computers that have different processor steppings or vendors—for example, migrating from a computer with an Intel processor to a computer with an AMD processor.
• Virtual machine configuration under one of the following conditions:
  
  • When the number of virtual processors configured for the virtual machine is more than the number of logical processors on the destination server.
  • When the memory configured for a virtual machine is greater than the available memory on the destination server.
• Consolidation of physical servers to virtual machines, or consolidation of multiple instances of Hyper-V to one instance.

http://www.microsoft.com/downloads/details.aspx?FamilyID=5c1ec14a-e9d7-46ea-9c6e-73d6bc4219b4

Documentation:

http://technet.microsoft.com/en-us/library/ee849855(WS.10).aspx