Refer to the sourceforge site for gusi downloads.

Mac/Demo/building.html

@@ -56,8 +56,8 @@ probably impossible without major surgery.
 
 <LI> You need GUSI version 2, the Grand Unified Socket Interface, by
 Matthias Neeracher. The original GUSI is obtainable from <A
-HREF="ftp://sunsite.cnlab-switch.ch/software/platform/macos/src/mw_c">
-ftp://sunsite.cnlab-switch.ch/software/platform/macos/src/mw_c</A>. At
+HREF="ftp://gusi.sourceforge.net/pub/gusi/">
+ftp://gusi.sourceforge.net/pub/gusi/</A>. At
 the moment Python is built with a slightly modified version of GUSI
 2.1.1, so it may be better to check the <A
 HREF="http://www.cwi.nl/~jack/macpython.html">MacPython homepage</A>