I bought a brand new pc this year .Came with vista on it .I used it for three days then reformatted and put xp pro on it.Never looked back.I hate vista.It still has so many problems.I'm sure dual booting is an option as it was with windows xp.With XP it is was as easy as making a partition installing XP on it.Then at boot you have a choice of which OS to boot to.
http://www.pronetworks.org/forum/about88231.html