Mstone is a mail performance measurement system. It can simultaneously test SMTP, POP, IMAP, and some HTML based systems. It measures transaction latency in multiple stages, and graphs the combined results from multiple clients.
A Bayesian spam filter for SMTP servers, based on Paul Graham's "A Plan for Spam", http://www.paulgraham.com/spam.html. Includes tools for spam-database maintenance & testing config. parameters. Supports sendmail & postfix; others soon. GPL.