Software Licenses and virtualization

I am mostly a linux user, but sometimes have to resort to windows xp/vista for MS Office and maybe coreldraw, so I usually use a dual boot. I recently bought a C2D laptop and have been testing its virtualization capabilities in ubuntu 8.04.01 with KVM and I have to say I'm really, really impressed!

But here's the question: I have one license of MS Office which I have already installed under Windows Vista. If I were to install it also inside a virtualized Windows XP environment to run inside Ubuntu, would that still be allowed under the licensing agreement? The box says "license for three PCs" (two other systems are already using this MS Office license)... I wonder if that refers to the physical machine or a single operating system?....

What about the Corel Graphics Suite X4? Would I be violating the license agreement if I were to install the suite in my vista boot and also inside the Virtual Windows XP box?....

Any input would be greatly appreciated!