RichNesse is a (mostly) WYSIWYG rich text editor for Fitnesse, utilizing a Fitnesse plugin written in Java and a configured version of the FCKEditor html rich text editor. All documentation is in the Wiki.
Very useful! The only problem is incompatibility with the new version of Fitnesse. I've written a simple method for installing. The details are hereafter: http://bit.ly/dcKvFP