Shoutbox

That stuff about VMWare Workstation isn't true, at least, I've never seen it.

Just get VMWare Server. It's free and lets you make virtual machines, the only downside is that you can't use sharing folders, but you can attach it to a Netbios network so you don't need them anyway.

With Wubi, I don't think you need to use a Virtual PC. It is supposed to add an entry to the Windows NT / Vista bootloader allowing you to choose XP / Vista or Wubi. Might not be Vista compatible though.. haven't checked that.