Lately I've been re-working on Mailboy which now has it's own web space. I've included a tutorial that is practically "copy pastable" when using Debian Wheezy.
I consider it beta, even though people are currently already using it, including myself, and it works fine. However, there may still be things like spelling mistakes, perhaps the install guide isn't so clear, etc. Feedback is welcome.
One of the new features is integration with Ejabberd, your users can now use XMPP using a single login.
I've also added a new template and gave it a logo, credits for that go to one of my brothers, thanks Allan.
More here: Mailboy