There are two ways to edit a local Wiki in Emacs. WikiMode and EmacsWikiMode. This page is about the latter.
The main Wiki-page about EmacsWikiMode is here: http://www.emacswiki.org/cgi-bin/wiki.pl?EmacsWikiMode (I removed the little blots of info here to that page.)
Check out the latest emacs-wiki.el mode. It makes storing a bunch of files in WikiFormat a real snap. There's even a one keystroke function to export the whole directory to an HTML Wiki! There is also an extension PlannerMode? for planning your day.
Note: EmacsMuse is considered to be the eventual replacement for Emacs Wiki Mode. http://www.emacswiki.org/emacs/EmacsWikiMode -- PeterWang