I'm looking for something like a server side WYSIWYG Editor...

What I want to do is to be able to log into an area, and be able to list all my text files [.txt, .html, .php, .js, .css, etc.] in their respected folders and allow me to edit them through the browser and save the changes...

The closest working example that I can think of would be Wordpress's Theme Editor. Anyone know what i'm talking about?