The archive and sign-up pages for the Wikipedia mailing lists are now at mail.wikipedia.org, so if someday we move the mailing lists to yet another server we should never have to change the links again. :)
Any old links via www.wikipedia or pliny.wikipedia should forward there automatically.
[ Aside to Jason: I still turn up links to wikipedia-l message archives on www.nupedia.com via google searches sometimes, but these give 404 errors. Any chance we could get /pipermail/(wikipedia|wikitech|intlwiki)-l/(.*) to redirect to mail.wikipedia.org? "In theory" a 301 response will also tell search engines to change their listings to the new location if they ever re-index the page. ]
-- brion vibber (brion @ pobox.com)