kmMail is a PHP-based mail program, based on the mail functionality of Keftamail and is being developed by current Kefta employees. It is meant to be a framework for putting a web-based mail program on your site, but is still robust enough to drop into your current site with little to no modification. The goals of kmMail are MIME compliance, speed, low overhead, and an enjoyable user interface.
Twiggi Web Based Groupware is a Web based groupware application, written in PHP4, using MySQL as its database engine. It was originally based on the excellent TWIG project. With many on-going enhancements, it is similar to Microsoft Outlook, and features the following modules: twiggi today, Mail, Contacts, Notes, ToDo, Bookmarks, and extensive online help (available in English and German). Twiggi has full language support for German, Dutch, Italian, and English.
eXtended Account Management System (XAMS) allows Administration of Unix, Web, FTP, DNS, and email accounts to manage a provider's typical userbase. Especially focusing on email account management, it enables you to easily create accounts, set aliases, and delegate domain administration to 2nd party resellers or customers. It uses PHP with MySQL or PostgreSQL as a backend, and is therefore able to manage tons of email accounts independently from your Unix/Linux accounts. Exim for SMTP and Courier for POP/IMAP are fully supported, but postfix, Cyrus, and qmail can be used too.