Download Virtual PC 2004 for free
Microsoft has made it's version of Virtual Workstation technology free to download. It's called Virtual PC 2004 with SP1. The virtualization world is getting better and better. Consumers are winners as first we got VMWare to make Virtual Server for free, then Microsoft made a similar move.
VMWare then created VMWare Player and made it free. So consumers are getting more and more things for free with better and better technology.
One can use software like VMWare Workstation or Virtual PC to install guest OS on top of an existing host operating system and can have it running at the same time. So for example, one can have Windows XP Professional running as the host OS and then on top of it can install Linux OS/Windows Vista on Virtual PC and then can run two OS simultaneously. It works great when people need to test applications or patches before deploying on the Network. Even for individuals works great for testing out hacks without damaging the host Operating System. It is also handy for learners of the new OS/application as they can network two computers together. Both VMWare and Virtual PC offers many more advanced features then the ones described here.
On a personal note I use VMWare Workstation for many good reasons and have been quite happy with it. But if you don't want to spend money and still enjoy virtualization technology, then Virtual PC 2004 is right there for you.