Macjordomo lets you quickly and easily set up your own Internet mail distribution system. This allows a large number of users to send email to everyone on a distribution list, just by sending a message to one central address. Macjordomo lets you configure the tool in a variety of ways for flexibility.
What's new in Macjordomo X
Version 1.6a3: Added option to just ignore messages from non-subscribers (rather than send a notice)