Duplicate profile folders?

I have very little knowledge of windows server so please bare with me. All of our workstations here are XP Pro and when I explore all users from the start button I see duplicate profile folders on many of the workstations such as User and User.domain. Can someone tell me why it?s done this and if I can remove the local profile folder without causing problems? All the users should be using the domain profile to log in.

Thanks in advance!