TidBITS: Apple to Allow Virtualization of Leopard — Mac OS X Server, not the workstation version.
This is pretty big news, even though it’s really only the change in EULA right now. It would solve a great many problems in hosting Mac OS X Server if VMWare ESX could run on Apple hardware. If you could make Xserves part of an ESX cluster, and you could limit the Mac OS X Server to running on just the Apple hardware in that cluster … that would be very good. But this is all wishful thinking and speculation on my part.