I know there is a monitor of this in Win2K professional and server, you can see all te open files in the shared drives or folders, by file, by user, by drive.

you can locate this monitor in
control panel / administrative tools / computer managment / system tools / shared folders

you could try also confile, this is a monitor that tells you the same, whic files are opened in a the current workstation or server. try to search the web for it