milter manager is a flexible and low administrative cost anti-spam system that can be used with MTAs that support milters like Sendmail and Postfix. It provides an effective solution by combining a range of existing milters.
FormSpamCheck is a PHP class to centrally manage several online form and forum spam services. It currently supports www.stopforumspam.com, www.projecthoneypot.org, and www.akismet.com.
A C++ extensible architecture.
An open virtual worlds server.