Seems Microsoft wants to leverage some buzz at VMworld and released Hyper-V Server 2008 R2 which is supporting a bunch of new features. You can check out their blog to see more info, the highlights are:
Up to 8 processors per physical server
Up to 64 logical processors
Up to 1 TB of physical memory
It is good that VMware has some competition to push it to continue to innovate and drive new and exciting things to market. Plus never, ever count Microsoft out, they still get a whole additional version number before folks consider their product "ready" to use, which means they will get lots of attention pretty soon.