The "net file" command shows you a list of the files that other computers have opened on the system upon which you execute the command, however it truncates long path names and doesn't let you see that information for remote systems. PsFile is a command-line utility that shows a list of files on a system that are opened remotely, and it also allows you to close opened files either by name or by a file identifier.
Just copy PsFile onto your executable path, and type "psfile".
PsFile works on NT 4.0, Win2K, Windows XP and Server 2003.
The default behavior of PsFile is to list the files on the local system that are open by remote systems. Typing a command followed by "-?" displays information on the syntax for the command.
usage: psfile [\\RemoteComputer [-u Username [-p Password]]] [[Id | path] [-c]]
PsFile uses the NET API, which is documented in the Platform SDK.
PsFile is part of a growing kit of Sysinternals command-line tools that aid in the adminstration of local and remote Windows NT/2K systems named PsTools.