Backing up large files

I need to ensure backup of some important files on some workstations. Now it’s done buy user starting a .bat file which copies his local files to network location where dayly backups are implemented. Is there a good way to establish these backups, thinking that files they copy somtimes go up to 2GB (these are outlook .pst files and users just don’t want to clear them up, but do need an uptodate backup of their mail). May be there is a tool which will allow to make incremetual backup instead of overwriting large files everytime?