Microsoft recently released the their WMI API's for Hyper-V. They can be found HERE. The WMI APIs extend Hyper-V management and tasks to scripting languages (much like the Virtual Server COM APIs).
What I found interesting was this little tidbit in a post by Mike Sterling, a Microsoft Community rep who frequently posts in the Hyper-V Technet Forum:
"We expect the Hyper-V WMI APIs to be used widely in a variety of ways such as:
· By third party management vendors who want to write tools to manage WSV (examples, HP Openview & IBM Director)"
I know IBM Director already attempts to manage VMware, it will be interesting to see what type of support they have for Hyper-V when the time comes around.