Now that Microsoft Vista RC1 is out (and probably available in less-than-legit versions), you can test out its features without having to create a separate partition or upgrade over your existing OS. Try VMWare, which is a tool that sets up a virtual machine within your PC.
A virtual machine is a software-created machine residing within a physical machine. You can define how much memory it needs, how much disk space, whether it has access to USB ports or to your network. You can even set it up so that it points to an ISO image. When you start up the virtual machine, it even begins a BIOS count just like a real machine!
Virtualization is a great tool for developers and testers or for those who want to check out a new OS. Simply create a virtual machine and install the OS in that machine. It’s great also to make “sandbox” machines, isolating them from your network or host machine. For example, I am experimenting now on viruses and malware to see how they actual work to damage PCs without having to create a whole new isolated network. It’ll be great also if you want kids to use your PC and restrict them from installing any potentially dangerous apps.
Another fantastic feature is that you could download a free VMWare player as well as “virtual applicances,” which is great if you want to create kiosk machines. No problem. And since many—if not all—appliances are also Linux-based, these tools are free and can be freely distributed.
Obviously, your PC should have enough hardware juice to run multiple PCs, but my experience is that, unless you do high-end gaming or media editing, you won’t need massive CPU power. You’ll need enough memory though to meet both the virtual OS requirements plus your host machine requirements. Ubuntu, for example, runs fine at 256MB virtual machine, so a 512MB host machine should work out fine. But if you plan to run Vista, that host machine may crawl.