Whizzywig is easy. It lets people create rich, formatted text through a web form. It actually creates HTML (or xhtml, if you prefer) but you need no HTML knowledge to use it. If you can use a word processor or email, then you can use this.
WYMeditor has been created to generate perfectly structured XHTML strict code, to conform to the W3C specifications and to facilitate further processing by modern applications. With WYMeditor, the code can't be contaminated by visual informations like