On ocassion Win2K ( which XP is based on) has the same problem. make sure your workgroup name is the same as the other comps and since XP IS identical to Win2K access to shared drives will be unaccessible unless a local user account is created on the Win2K/Xp machine for those trying to access shares from other machines.

And not to flame but frankly I am tired of hearing MS sucks I'm going to Linux argument. I have used Linux and would still be using it if it properly recognized my RAID controller and my current RAID 0 setup at install. I wouldn't give up my Win2K/XP systems because of it. More than Likely I'd have all three, but since I'm an avid gamer a complete transfer to Linux is unfeasible at the present.