The University of Bristol has a list of WYSIWYG Editors [1]. I found this that link on the ComposIte mozilla project page.
ComposIte is a chrome overlay which enables a streamlined Mozilla Editor for html composition in textareas. To use the editor, hit ctrl-e in a textarea. Alternately, you can turn on an \’Edit with Composite\’ button in the Composite prefs (v0.0.5 and higher).
ComposIte is a port of Eric Hodel\’s (aka DrBrain) LiveLizard editor. It is hooked up via a overlay with a single call to GetElementsByTagName.
[1] http://www.bris.ac.uk/is/projects/cms/ttw/ttw.html
[2] http://composite.mozdev.org/
