In my UNIX class, we were intruduced to Cygwin, which is a simulation of UNIX that runs on top of your Windows operating system. I also had a try of another method of running a real operating system on top of Windows using a cool concept called virtualization. By using a software called VMWare, I can run other appropriately packaged OS. I have FreeBSD and PC-BSD running OK without having to reinstall Windows or create partitions! Its a great feeling to have more than one operating systems running on one PC!