I have already asked this question, and the answer is a resounding Maybe.
Be sure to make an image of your XP system, because if something goes wrong,
and this is a Beta, you may have to reformat your hard drive and restore
from the image to get your XP system back.
If you don't have an image, you will lose everything.
If you dont have software that you can use to make and restore an image, or
you are not sure that you have the procedures down, you run a very real risk
of losing your XP system.
One of the gotchas is that when you start to load Vista, it is very easy to
format and load on the partition that XP is on by mistake. The Vista
installer doesn't tell you which partition is which.
Todd