You can find ready to go Mac OSX VMs online (torrent/usenet etc., usually 2-6gb).

They worked on any PC I tried them on, but without GPU acceleration, although I had to install a VMWare MacOS enabler (that was bundled with the VM) because VMWare disallows OSX by default I believe, might be different with Virtualbox.

You can run MacOSX in virtualbox if you the moon aligns for you (I've had some machines it worked ok and others I just couldn't get to work).