@ @ AC (Downgrade) / Dave K
Yes you need Vista Business or Ultimate and normally i get a XP Pro key with no problem,
then you use your copy/iso of xp you downloaded and input the key they gave you over the phone during the downgrade and away you go!!...last time i asked it also allows you to (for what ever reason) upgrade back to the version of vista you orginally got..so im told.
or just use suse + wine...