This HOWTO is not about Network filesystems, but I should mention them.
There is a brief list of some which I know:
I haven't see yet any good page about writing DOS filesystem drivers (Network redirectors) on the net. The best source is Ralf Brown's interrupt list and iHPFS source code.
For more information about writing FS drivers for Windows NT see http://www.ing.umu.se/~bosse/ by < bosse@acc.umu.se>.