I installed Virtualbox last night as I wanted to be able to use Octave and MacPorts was not working. I downloaded the Ubuntu x64 iso and installed Ubuntu in Virtualbox. I can not believed how well it worked. I gave Ubuntu 4GB of RAM and 128MB for video. I allocated 40GB max to the Ubuntu install. Ubuntu installed in about 5 minutes. After completing I am able to run Ubuntu full screen on one desktop and OS X on another.