The amazing folks at hexxeh have now made the VDI files public which means anyone with a copy of Virtualbox can now install Chromium / Chrome OS on to their computer. To use this VDI files, just install VirtualBox and create a new virtual machine in it. Download a VDI file.
The links to the VDI file are given at the bottom of this post. Download it and extract it. When the app asks you if you want to create a new a hard disk drive for the new OS or use existing one, just browse for the VDI file that you downloaded earlier.
It will then ask you how much memory you would like to assign the the image. Go for 2GB if you have 4GB or more RAM on your computer. Otherwise, even 1GB is more than enough for him. [download link]