As pointed out by indiajoe, chmod (and perhaps chown) is probably the way to go here.
However, exactly how to do it depends on a couple of things. Do you want this user to be the only person who can write to it? Or do you want all users to be able to write to it? Or perhaps a set of users, eg tom, dick and harry, but not bill and ben?
Last edited by evo2; 11-17-2009 at 07:45 AM.
Reason: No need to quote