You can check out
www.fckeditor.com
It's largely based on JavaScript, but it comes with ASP.NET components that allow you to drag and drop editors on your page.
I've been using it in a couple of projects, and so far it has worked wonderfully.
Especially the integrated image / file management capabilities are really great.
Cheers,
Imar
---------------------------------------
Imar Spaanjaars
Everyone is unique, except for me.