Hyper-V PM Eric Bahna recently recorded a video demo of the new Hyper-V Windows PowerShell cmdlets in Windows Server "8* Beta. The complete demo is about 21 minutes long.
For convenience, I also made three shorter versions currently available on YouTube
The wiki article Hyper-V Cmdlets In Windows Server 8 links to all four versions. If you would like to run the demo yourself, the script is available for free at: http://aka.ms/sd4fra the script to configure the environment for the demo is at: http://aka.ms/bzxqkr
You can read more about Windows PowerShell in Windows Server 8 on TechNet. The Hyper-V goodness is here: Hyper-V Cmdlets in Windows PowerShell.
See also Matthijs's blog: Using native PowerShell cmdlets with Hyper-V in Windows Server “8”