I think a good idea would be to set up a WikiWikiWeb site for GNUstep
documentation and discussion. If you're not familiar with the Wiki
concept, a good (and quite relevant) example is http://www.cocoadev.com, a Wiki dedicated to Cocoa development on Mac OS X. Another example is
the Wikipedia (http://www.wikipedia.com), a Wiki encyclopedia.
Basically, in a Wiki, anyone can contribute. Anyone can create a page,
or edit a page. It stores page history, in case someone comes along and
decides to replace an entire page with the word "POOP" or to post
advertisements (those have happened on CocoaDev a few times). That way,
not only could GNUstep developers write good documentation, but anyone
can add documentation, or improve on anyone else's documentation.