VMWare on Mac OS X!

Yes! VMWare is porting to Mac OS X.

The ultimate development machine is on its way. The slick, easy to use Mac OS X, the power of the Unix command line, and the ability to run Windows, Mac OS X, or Linux under VMWare!

(Note: I think VMWare is vastly superior to other virtualization solutions because of the ability to snapshot your virtual machine and jump back to that point in time. Its invaluable for builds.)