It is possible for administrators to use the Computer Management's Shared Folders tool to see what shares are currently in use, what files are currently in use and which users are currently using the objects. But I don't see an indication of whether the files are locked, how they are locked or what application is doing the locking.
It is possible to grant users access to view this information by creating a custom MMC console with the Shared Folders snap-in. The console can be pre-configured to view only a single system or allow the user to change system context. Be sure to set the console to user mode before distributing to non-administrative users.
This was first published in March 2003