Modest system requirements, decent performance, simple installation and upgrade, no database required - all these make RainLoop Webmail a perfect choice for your email solution.
OutlookAutoProcessing is an Outlook 2k3-AddIn which enables simple processing of incoming mail far more complex then Outlook rules. The main example is the automatic creation of Outlook contacts based on mails from a Typo3 system.
Is an ASP.NET webmail application written in C#. It uses a POP3 or IMAP servers as the mailstore and sends mail through a SMTP server. You can compose HTML messages, search your inbox, read complex mime messages and much more. .NET and Mono compatible.
This is a webmail server intended for personal use (though of course, commercial use is not forbidden, it's just not my focus with this project) using secure http. Since it has its own https server built in, it does not require complex configuration.