Windows HyperVisor Public Beta available Q1 2007.
In the keynote we saw Virtual Machines running on Windows Hypervisor. 1 VM was a 64 bit guest, One VM had 8 (virtual processors), they were able to added RAM on the fly. No downtime, real hot-add RAM.
Later in the demo we saw the System Center Virtual Machine Manager automaticly added RAM on the fly.
HyperVisor willl be available 180 days after Longhorn Server RTM's