Installing OS X Guest on OS X Host update: After upgrading to the latest version of VirtualBox and following the first answer at Install OS X in VirtualBox on iMac?, I am now getting the Still waiting for root device.  If I follow the answer about the extra data, I get an Apple logo and a spinning wheel, then I get a crossed-out circle and a spinning wheel.




original question: I have to do some testing with a few different versions of OS X.  I have a machine running 10.6, and I have a USB drive partitions with various OS X installers.  I made disk images (*.dmg) of each of the 10.7 and 10.8 partitions, but when I try to start up a VM, I get (with the 10.8 disk image) if I have EFI enabled



or 

FATAL: No bootable medium found! System halted.


How can I install these various OS Xes on an OS X host?

Thanks!
that only works with Vmware Fusion (since Version 5 i think not really sure about that, so maybe just go for the latest Version) and only with the newer OS X (Snow Leopard and later) as Clients.
Sorry no Virtualbox now, maybe Oracle will also Support OS X in Future.