Actually SpamAssassin runs under *NIX but there is a Outlook version. I personally use SpamNet and it works quite nicely. Nearly all of the spam is caught.

SpamAssassin is an open-source product aimed at UNIX systems. However, Deersoft sell Exchange and Outlook versions of SpamAssassin, and there is also Spamnix, a commercial Eudora plug-in. Other interfaces for plugging SpamAssassin into your mail systems are listed on this page.

- Trevor