Craig, the forums I have seen, show that installing OSX onto a windows PC is a very complex process.Involving certain hardware, and needing modification of the OSX programme. But the other way round works fine and is easy. If you have an intel Mac you can install Windows in an option boot with Boot Camp which comes with the new OSX Leopard. Or if you install a Virtual programme such as Fusion or Parallels you can have dual boot, or multi boot.
I am running Vista on an iMac and it works very well for most of the things I need, but fast games do need better video cards.