Buni Meldware Communication Suite is an enterprise groupware product providing an email server, calendar server, and a Web mail client. The Web mail portion is written using Adobe's Flash and provides a rich cross-browser experience. Protocol support includes IMAP, POP, SMTP, iCAL, WCAP, and more. It uniquely supports full database email storage as well as file system storage of emails on major database platforms, and is easily installed via a Web Start graphical installation process.
Gutuma is a feature rich PHP newsletter/mailing list management tool that is designed to be easy to install and use. It doesn't require a database, yet offers multiple lists, import and export from CSV, file attachments, drafts, AJAX subscribe gadgets, administrator email notifications, MD5 protected logins, and batched deliveries that can be driven by a cron job.