What is it?
Virtualisation is using a software application to run other operating systems inside a window, known as a Guest, within a real computer, known as the Host.
You can run an entire operating system, Windows 95, Windows 98, Windows NT, Windows 2000, Windows XP, and Vista. Use an open source operating system such as Linux and even run a PC as a Mac! You run any application programs for that operating system with it, while your original operating system, acts like it is just running another application.
How do I use it?
Most people just look at you like a rabbit in car headlights when you try to explain it to them though. LOL