WMD is a small, simple WYSIWYG-style HTML editor written in JavaScript. Type your text in Markdown, and WMD will convert it to HTML behind the scenes, with optional realtime preview. See the online demo for more information.

WMD works in recent versions of Firefox, Safari, Opera, Konqueror, and Camino, as well as IE6 and IE7. IE8 support is on its way.

I'm refactoring the code, and will be releasing WMD under the MIT license soon. For now you can download the most recent release (wmd-1.0.1.zip) and use it freely.