JSP-based web email system, support large numbers of concurrent users, multi-level folders, multiple-languages. By PLMatrix Technologies Company.

Servlet-based web email system, designed for scaling to large numbers of concurrent users. Intended for large universities or enterprise-level mail systems. [Commercial]

Web-based interface to Unix system mailboxes. Compare it to the systems Hotmail, and YahooMail use. [LGPL license]

A web-based POP3 email client that also includes a calendar, notepad, webdrive, automated email reminders, contacts, P2P sharing, and web-based administration. One installation can support multiple users and each user can setup as many POP3 accounts as they need. Servlet-based. [Shareware]