Duplicate of http://stackoverflow.com/questions/39159/is-it-possible-to-run-osx-in-a-virtual-machine
I'm looking to install Ubuntu as the main OS on my Macbook Pro. However, I'd like to still access OS X without rebooting. I know it's possible to have OS X be the host OS and run Ubuntu inside it. However, is the opposite possible? Can I have Ubuntu as the host OS, running a VMWare instance of Mac OS inside it? Has this been done?
Nope, Apple has not licensed VMware to do this. I believe this might be possible in the server version of Leopard at some point, it has been some time since I read this somewhere however.
The only version of OS X you can virtualize is OS X Leopard Server and only if the host OS is OS X Leopard Server.
http://blogs.vmware.com/teamfusion/2008/06/virtual-leopard.html
UPDATE: You may be able to run OS X Leopard Server on plain OS X Leopard. The wording is so confusing. Read the UPDATE at the bottom of this Ars article.