Under "The Perl Community section", a link called "mail lists". Click on this and on the page that comes up click "Submit New List" on the left. Hope this helps.
Either I'm being exceedingly dense or we are not understanding each other (...mmmm... probably both...). I am looking for a place to start a mailing list, not to join one, or to notify the perl community at large of the existence of one. It looks like the page you're suggesting will let me announce the existence of a list, not create a new one. I think.