Haven't seen him here in a while but Penguinisto was the Linux fan(atic) :-) He'd probably know the latest developments. VMWare is pretty much the state of the art in emulation that I'm aware of and I think they just started offering a free version. You should be able to run a Linux VM under XP/2000 or vice versa using their software. Keep in mind that performance is almost always going to suffer to some degree under emulation though the new chips coming from AMD and Intel are going to put some of the virtualization in hardware which should help in that regard.

"Democracy is a pathetic belief in the collective wisdom of individual ignorance." - H. L. Mencken