You don't really even have to use a plugin just to have a WYSIWYG text area in a page. InteractiveTools has a free product called htmlArea that provides a WYSIWYG text area editor in both IE and Mozilla (1.3 or greater). It's still in beta, but it does work in Moz 1.3.
http://www.interactivetools.com/products/htmlarea/
This is the kind of thing you wish would just work in every browser out there, but IE is available on every Windows computer out there (sadly this is a majority), and Mozilla runs on damn near everything else.
