I just came to know the technique (which I was looking for from a long time..) by which we can run Linux/Unix on Windows (through Virtual Machine 2007)..
You can download the ISO images for various linux versions from here,
http://www.linuxlinks.com/Distributions/LiveCD/
And configure the Virtual Machine to boot from these ISO images directly! Its easy and every good...
Right now, I am downloading ubuntu (to see why Dell started with ubuntu...) and going to see whats in there.
Stay tuned.. 