Sieve interface for spam filtering scripts?

[Mike Brodbelt]

> Squirrelmail has a sieve plugin. Maybe give that a try ;)

I'll second that. I'm using Squirrelmail and the sieve plugin in
production, and can vouch for it. Works very well, and users have no
problem setting up spam filtering. I use sendmail/milter/spamassassin to
tag all incoming mail - it's then up to each user to enable the filter or
not for their account, as they so choose.
The Sieve plugin also provides easy set up of out of
office/vacation/canned autoresponse to some aliases and various other
things.
Mike.