Open source virtual machines on your desktop. Ever wanted to try a different operating system but didn't want to load it as your main system? Every wanted to run your old copy of Windows 98 on your Vista pc?
Virtualization lets you run loads of different operating systems (including server versions) from within your normal operating system. You can use these virtual machines with all of the resources of your laptop/desktop without affecting your main operating system. If you use server software as a virtual machine, you can even get clients to log onto it as if it were a real server.
Ade's Comments:
This is a fantastic piece of software if you want to try other operating systems. You simply create as many virtual machines as you wish, assign resources to them and away you go - the operating system appears in a window. You can switch between your main OpSys and the virtual one. Very handy!