6XMailer is a PHP POP3 mail reader with support for HTML mail, MIME attachments, embedded mail content, multilingual ready, and themes. It has an address book and centralized configuration file.
Acorrer is a plataform of email and calendar. Written in PHP with database MySQL
Webmail client for call center agents. Designed to efficiently manage and report on a large number of emails to a small number of email addresses. Specifically designed with webforms in mind where one email address may receive over 1000 emails per day.
php/MySQL based webmail program. Currently only supports pop3, IMAP is in the works. Has a notebook, a favorites organizer and an addressbook.
Aleph is mail/news software written in Java. It has such features as: 1. Internationalization support (especially encodings). 2. Cutomizeable Swing multiplatform GUI. 3. Suppor for POP, IMAP, NNTP, SMTP protocols. 4. Plugins.
AlphaMail is an accelerated web mail interface with a C++ middleware layer that is more effective than an IMAP proxy which is a highly scalable (10k+ users). The interface includes modern features, Section 508 compliance, and universal browser support.
A GUI-based email application capable of recording, compressing and sending voice messages.
After one year without development of the XForms based Unix email client XFMail, the coding has started again. The GTK is supposed to be the toolkit of choice and so we will take XFMail's core, restructure it, and port it to the Gimp ToolKit.
"Archive This" is an add-on for the Thunderbird email client that provides shortcuts for filing messages into folders rapidly and efficiently.
Attachment Reminder is an Add-On (extension) for Mozilla Thunderbird that scans outgoing email for user-defined keywords (or just use the default list), and prompts you if it looks like you wanted to attach a file but didn't.
Email2Fax and Fax2Email gateway for Asterisk, that could be integrated to your own existing Asterisk.
BasiliX is a webmail application based on PHP and IMAP, and powered by the MySQL database server. It supports simple mail actions, sending/receiving attachments, an addressbook with group capability, configurable, multiple languages and multiple folders
Belarusian localization of Mozilla Application Suite, Mozilla Firefox, Mozilla Thunderbird, SeaMonkey.
Email client (to be) written in C# and GTK# (primarily intended for Gnome, but cross platform though). Bella stores emails as individual .eml-files.
BlogMail software is a CMS and a Webmail application integrated in one. It's based on WordPress MultiUser and has all the functionality of this, like RSS and comments, plus support for LDAP, smarty templates, automatic subdomains and antispam filtering.
BNM helps you design and send massive emails in HTML format
Bulk Newsletter Platform(BNM) provides the components necessary to send bulk email in HTML format. BNM is written in PHP and it is appropriate to work either standalone on a server or embeded in an existent website. It is an easy to use, marketing tool which allow the user to create and send massive advertisements and newsletters in HTML to his mailing list.
The goal of Buoyant Mail is to provide as fully fledged of a PHP driven mail suite as technologically possible. It will look appealing (will also be themed, so any custom look can be created) and will include a calendar and address book.
CSCMail is an X/Gtk based MUA. It supports the POP3 protocal and can also read mailspool files/directories. It supports multiple accounts, filters, GPG, MIME, Spellchecking, HTML Mail (view only) and a host of other features.
CangrejoMail it's a mod of the popular webmail "SquirrelMail". All the html code has been changed to XHTML, this way, all the interface is handle by CSS with the possibility to work with themes.
Carassius is an Email client unlike any other. In addition to a new intuitive approach to the regular email protocols (POP3, IMAP, SMTP), Carassius also handles the major Webmail services including Gmail, Yahoo! Mail & Hotmail.
CellMate Bot currently allows google queries and aim functions through OSCAR. Made to be used form your cellphone's AIM client, CellMate Bot will be updated to include email, news and map directions in the future. For now, you can use Google SMS.
CentraView - Browser based Enterprise Java (J2EE) Contact Management, Groupware, Collaboration, CRM, SFA, Project Management software. Run locally or as a hosted service. Built on Apache Tomcat, JBoss, MySQL, Linux (Fedora, RedHat and others) & Windows
CherryMail is a webmail application. CherryMail started to experiment with CherryPy, Genshi, and AJAX. A webmail client seemed like the obvious application to build as most of the popular open source webmail apps (SquirrelMail and Horde) are lackluster
cherrywebmail is a python IMAP4 web-based client that uses cherrpy http framework.
This is planned to be a Mail app written COMPLETELY in Python. We are planning to implement a GUI using the standard Tkinter modules. We are aiming for a fast, lightweight mail application.