This is a system you are most probably already using, if you are akin to test driving various operating systems and software combos: VMware Player is a free virtualization software tool that can be easily applied to set up different, “virtual PCs” inside a single OS installation. Very useful, if you do not want to mess up your primary system each time a new interesting tool or OS comes available. I followed these instructions to set up Ubuntu 9.10 Karmic Koala to run as a virtual machine inside my Windows 7 workstation. Seems to run just fine.
frans goes blog 
After some more experiments, it looks like that at least on my workstation, the virtualized Ubuntu is too slow for anything other than basic testing. It also appears to have problems to keep connections open to my shared network disks/resources, which is not too nice. But the basic idea is good and VMware virtualization application appears to do at least decent job.
More experiments, and the Ubuntu box suddenly starts reacting faster and can again also connect to my network shares. Weird. Perhaps there are some resources that the VMware box puts onto hold into swap disk or something, and then when you return to the box after a longer break / sleep state, it takes some time for it to ‘come alive’ again? Don’t know, but now at least it is running fast again.