This is one of those things that has so many suggestions that it drives you to distraction. Having tried a whole raft of them I was thrilled to find this simple solution that works! It's a page called PLESK Mailman Cheat Sheet and has all the info you need in just a few clearly written and easy to follow lines:
http://www.bigsoft.co.uk/blog/index.php/2010/06/07/mailman-cheat-sheet - thank you David Newcomb for such a helpful page!
