Looking for a database-driven email "contact manager" application

I'm going to be collecting lots (a few thousand) email addys. Each of
these people will be interested in recieving mail on one or more
topics, with an open ended and growing number of topics. Mailman with
a BD application behing it might be ideal as it would let users add
and delete themselves and each topic would have it's own email list
name identity.

Any suggestions for a PHP/mysql application to do this?>

Thanks

-- 
a d y k e s @ p a n i x . c o m 
Don't blame me. I voted for Gore.