Robert Jones at ONLamp.com - Rich Web Text Editing with Kupu:

"Kupu is an open source application, written in JavaScript, that implements a flexible, full-featured HTML editor that runs in a web page without any special plugins. Its primary use is as an embedded editor in content management systems (CMS), like Zope or Plone, where it allows users to create their own web pages. Its design is flexible enough so that you can embed it into pretty much any web application without too much difficulty."