The EULA forbids you to run OS X on non-Apple hardware though.
"to install, use and run up to two (2) additional copies or instances of the Apple Software within virtual operating system environments on each Mac Computer you own or control that is already running the Apple Software, for purposes of: (a) software development; (b) testing during software development; (c) using OS X Server; or (d) personal, non-commercial use."
"They" being someone that posted an image on bittorrent? Apple doesn't license OS X for VMWare anywhere except Apple hardware. You can't even run a 10.8 guest on a 10.7 host per their license, which is really annoying.
VMWare ESXi (and Fusion too, I expect) runs legitimate installations, with no hacks required, as long as it's on Apple hardware. You need the InstallESD.img file from the OS installer.
For VMWare Fusion, not VMWare Workstation, I believe, as Workstation doesn't have an OSX version, and as others have said, their license doesn't allow for running a VM on non-Apple hardware.
"to install, use and run up to two (2) additional copies or instances of the Apple Software within virtual operating system environments on each Mac Computer you own or control that is already running the Apple Software, for purposes of: (a) software development; (b) testing during software development; (c) using OS X Server; or (d) personal, non-commercial use."
http://www.apple.com/legal/sla/docs/OSX1082.pdf