Runnng Win 8 on system with existing Win 7?

I've never played around with VMs, but I want to check out Windows 8. I'm running Windows 7 Professional on my current desktop, with the OS installed on a 128GB SSD. There is also one HDD in the system.

What would I need to do on this system to run Windows 8 in a VM? I'd prefer not to use any SSD space, so putting it on an existing, or even a different new (I can dig up an old 320GB HDD)?

Just plug in an extra HD, format it, install VMWare, and use the image to install..