Best way to hook into file system events?

Here is the idea. Essentially I want to
know when a VPN client is trying to open certain media types (mp3, wmv,
etc) and instead of opening them on the server-side machine, stream
them to the VPN client. So how can I know when a file is trying to be
opened? This seems like a Win32 Hook to me, but after some reading it
seems as though there is no hook into the filesystem. What is the
standard way to do this? Is something available in the Windows SDK?Thanks!Stephen ...