Yet another little program.
In this case, it's called rascan, and it's a rewrite of Inter7's simscan.
What does it do? It easily hooks clamav and spamassassin into your qmail-smtpd setup, so you will not accept viruses in your server, and tag spam.
It still lacks some features, like bouncing messages based on spamassassin hits, or blocking attachments, but it has at least one feature simscan lacks (adding footers to messages).
It's still alpha, so I wouldn't put it on a production server, but it may even work ;-)