CommercialWindows: Commercial products you can buy and install for Windows.
Open-source Products
Jocafi Brazil contributed with a front-end to JSpamAssassin. It is a POP3 Proxy Server developed in Java (platform independent). It has a friendly GUI and acts as a communication interface between the user POP3 server and Apache SpamAssassin. It runs on all OS and works with all e-mail clients (Eudora, Pegasus Mail, Netscape, Thunderbird, Outlook Express, etc.).
TheFreeSpamFilter is a complete VMWare Virtual Machine that acts as a spam filtering 'appliance' for your MS Exchange systems. There are 7 'how-to' videos designed to get you up and running. The system has a web interface for users to manage their own quarantine, and works with Exchange 2000 / 2003 / 2007 / 2010. Spamassassin and ClamAV are used to filter spam and viri from incoming internet email. The appliance will spool mail for you in the event of an Exchange outage.