Apple is allowing owners of OS X (client version) to run multiple virtual copies on the same machine, reports MacRumors.
“Previously, Apple extended this ability to Mac OS X Server only. Running separate instances of Mac OS X should be possible under virtualization solutions such as VMware Fusion and Parallels. This functionality allows you to deploy different sandboxed installations of OS X, typically for enterprise purposes.
The Golden Master version of OS X Lion (10.7) just released to developers includes the final end-user licensing agreement (EULA) which reveals that users can run up to two additional instances of OS X Lion on their same machine without a need for extra licenses.
From the 10.7 EULA:
(iii) 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.”
Read more: http://www.macrumors.com/2011/07/01/os-x-lion-allows-running-multiple-copies-on-the-same-machine-virtualization/