I've been re-working on this a bit lately, updating code and adding a few new options and features (like XMPP). I consider it beta, like everything I do, but it should work.
Mailboy is a web based mail server administration tool. It comes with a full "howto" guide, uses commonly available Free Software and if you start from a new Debian Wheezy system, should be easy to set up.
The idea of Mailboy is not to be a "professional email solution", but rather a "friends host friends
You can read more on the projects new website
, there's explanations, a howto and screenshots.