As a recent Mac convert, who plans to do Mac software development but hasn't started yet - is there a way to copy the existing mountain lion install on my Mac to a VM image so I can test on ML after I upgrade to Mavericks?
However, I found—at least with Parallels—you can't just take an existing hard drive image and use that: you have to create a new virtual machine, install Mountain Lion from scratch on it, then use OS X's Migration Assistant to move everything over.