I took the plunge. To install the usenet.php file in the administration, all you need to do is add this:
Right under "makenavselect("Templates","<hr>");"
// *************************************************
makenavoption("Options","usenet.php?action=options ","|");
makenavoption("Groups","usenet.php?action=groups", "<br>");
makenavoption("Spam Control","usenet.php?action=spam","<br>");
makenavselect("USENET Control","<hr>");
The rest, you'll have to hack out by hand. It's complex.