The mail manager I use is called MajorMajor, and the mail server is called Weasel. They're both written in Modula by a very good programmer in Australia called Peter Moylan, who teaches CS at the University of Newcastle.

They're intended to be simple, robust, and easy to use. So... no fancy stuff, but the basics are all there and I can prolly get one set up in fifteen or twenty minutes. The only issue is that in order to properly support handling mail for iwethey.org, I'll have to get Weasel Pro, so that I can support different email addresses for different domains; the only other option would be for me to set up another machine to host it. That'll take me a few days...