The base code for the wikiwyg environment is maintained by SocialText
and can be accessed via their wikiwyg svn repository at
http://svn.wikiwyg.net/code/trunk/wikiwyg

The Mediawiki extension that enables wikiwyg to work with Mediawiki is being released to the community for further development.

In it's current state, the "Extension" is actually 2 extensions and a patch to MediaWiki.  The two extensions are in share/MediaWiki/extensions

MediaWikiWyg.php - the glue code that allows Mediawiki to work with Wikiwyg
EZParser.php - Adds a simple interface to the Mediawiki Parser.  Used
to generate the HTML view when switching editing modes

The patch is available as share/MediaWiki/mediawiki-1.7alpha.patch.
The patch could conceivably be removed once the extension was able to
change the way that templates and some other similar things are
rendered, and once it is possible for an extension to allow a piece of
JavaScript to be included before wikibits (or if the frame-breaking
code could be somehow modified so that an extension could disable it).

By default, the code is expecting the entire directory (the directory
containing this README file) to be checked out in the documentroot of
the site, so you may need to adjust the paths to some of the
JavaScript files if that is not the case for your setup.

Let me know if you have any success with it, or if you need some help figuring out how to use it.

Jason Richey <jasonr@wikia.com>