I did a webmin module to control ZM.
It does quite few things: controls zmpkg.pl (start, stop, restart, status)
no multilanguage... but is a start...
here it is:
http://www.davidemorelli.it/public/zoneminder.tar
to install:
like any other webmin module untar it in /usr/share/webmin so that you get a new dir /usr/share/webmin/zoneminder, update /etc/webmin/webmin.acl, delete /etc/webmin/module.infos.cache.