Origins of Zmailer are in  University of Toronto:

       ftp.cs.toronto.edu:/pub/zmailer*

However a lot developement has happened by Matti Aarnio at his
three systems in Finland.  Improved versions are available on:
       ftp.funet.fi:/pub/unix/mail/zmailer/

       There is a mailing list:
               <[email protected]>
which runs around this mailer.  Also archives are available.  Join to
that list by sending a request to   <[email protected]> (there
is a human behind it) -- or (preferrably) via  <[email protected]>
by sending it a message with following kind of text in the body:
       subscribe  zmailer  Your Own Name

               /Matti Aarnio <[email protected]> 4-Jun-91, 20-Oct-95