gather files from multiple computers

i’m administering a network with least 10 computers (all with xp os) and they are connected in a network with a win2k3 server. I need to gather files once in a while from those computers so that the users will not bother to transfer files from their pc to the server. how can I do this. do i need an additional software for this or does the win2k3 server has a function to gather files from remote computers?
thanx.