spam question

what do you guys use to filter out spam? Our mail server is outsourced and does not provide spam blocking. Is there some kind of proxy that i can use to filter spam? I have found a few options but none of them seem to do pop3 spam filtering.

even better would be a system that connects to the mailboxes and filters spam on the server moving the spam to a different mailbox for review.


thanks.

Something like this? It's freeware and does the job :)

If you are on a unix system.

http://www.spambouncer.org/

Thanks guys. These look like they may work.