Arvind has documented the process for adding HTMLArea to MovableType. I'm thinking this is the perfect solution for my college football blog. We've got lots of authors that don't do English, let alone HTML.
My one concern is that I've heard that it produces some fairly sloppy code. Now, "sloppy code" is a very subjective thing. I'm mostly concerned with it working versus meeting every single web standard. Anybody have any experience with HTMLArea?