Ecartis is a open-source (GNU License) software package that administers mailing lists (similar to Majordomo and Listserv). Take a look at Ecartis' feature list, and see the advantages it has over other similar Listserver packages. (anti-spam hooks, ability to strip down MIME messages and remove their attachments, virtual hosts, just to name a few). Go to the download page to give Ecartis a try!