Mailman and Groups

Hope this will be of interest: http://drupal.org/project/mailman_groups and http://netgenius.co.uk/project/mailman_groups

Overview

The Mailman Groups module provides a level of integration between Organic Groups and Mailman mailing lists and compliments the existing Mailman Manager and User Mailman Register modules. It is probably particularly relevant to sites which operate a large number of Groups and/or Mailing Lists.