Thunderbird is a total redesign of the Mozilla mail component to produce a cross-platform, stand-alone mail application using the XUL user interface language. It has many new features, among them the ability to customize your toolbars the way you want them. a new look and feel with a large number of downloadable themes which alter the appearance of the client, and the ability to add UI extensions.
The PortalSys Addressbook is designed for clients who use Outlook on the desktop but use Linux as the mail system. It allows you to easily integrate Outlook with your Linux system's addresses. The system is made up of two parts: an Outlook service for your Win32 clients and a server-side application to generate and update your addressbook as often as you like.
Elmtree Express Server is a realistic alternative to the Microsoft Windows server plaftorm. Express Server is a workgroup server solution, providing your business with integrated email, print management, and data storage functionality, all in one easy package. It includes an email server, a central address book via LDAP server, a DHCP server, a central file server, a print server, automated daily backups, GUI administration tools, and more.
Tine 2.0 is a Web-based groupware solution that focuses on usability and correctness. To achieve these goals, the project uses usability experts and covers most of the code by unit tests. It contains support for contacts, tasks, calendar, email, CRM, VoIP integration, a time tracker, ActiveSync, and a flexible rights management system.