[thelist] Unsubscribe procedure (not from this list!)

[Jay Blanchard]

[snip]
I've created a simple PHP script that allows users to subscribe and
unsubscribe from a mailing list using a web interface.

This is all good, but I've been wondering today how would I go about
implementing the functionality to allow a user to be
subscribed/unsubscribed from a mailing list using either the subject
or body of an email address?

I've used PHP's imap functions to read in messages from a particular
mailbox before, but implementing this as a solution would mean having
a cron job set up to periodically check the mailbox.

Are there other ways of acheiving the same goal?
[/snip]

Zend has several things that may help you here
http://www.zend.com/codex.php?CID=11