Chandler is a standards-based "Note-to-Self Organizer" designed for personal and small-group task management and calendaring. It consists of a desktop application and Chandler Hub, a free sharing service and Web application. You can also download and run your own Chandler Server.
EGroupware is a Web-based groupware suite. It contains many modules, including Calendar (personal calendar and group scheduling, notifications and alarms), Mail (IMAP only), InfoLog (todos, notes, and phone calls linked to contacts/CRM), Contacts (an address book for storing and sharing contact information), ProjectManager, Tracker (bug or incident tracking), TimeSheet, SyncML, CalDAV & CardDAV support, and SiteMgr content management
The Gordano Messaging Suite (GMS) is a highly flexible and reliable suite of messaging products. Customers can choose which components meet their needs from email, Webmail, collaboration, instant messaging, calendaring, SMS, and list server software all of which can be complimented by high level anti-spam, anti-virus, and archiving options.
GroupOffice is a groupware suite that takes your office online, implementing online collaboration and CRM. It allows you to share projects, calendars, files and email online with co-workers and clients. It is easy to use and fully customizable. It also features synchronization with PDAs and Outlook.
Horde Groupware Webmail Edition is an enterprise ready browser-based communication suite. Users can read, send, and organize email messages and manage and share calendars, contacts, tasks, and notes with the standards compliant components from the Horde Project. It bundles the separately available applications IMP, Ingo, Kronolith, Turba, Nag, and Mnemo. It can be extended with any of the released Horde applications or the Horde modules that are still in development, like a file manager, a bookmark manager, a forum, or a wiki.
Inverse Lightning enhancer plugin enhances the functionalities of the Lightning calendar plugin for Thunderbird. It is meant to add better integration with CalDAV compatible servers such as SOGo. It provides support for CalDAV freebusy information in the scheduling interface and in the addressbook. It manages the iCalendar organizers by taking into account the identities configured in Thunderbird. And it fixes bugs found from time to time in Lightning which are not yet fixed upstream.
Inverse SOGo Connector for Thunderbird is an extension which transforms Thunderbird into a full DAV client for groupware servers such as SOGo, OpenGroupware.org, and Citadel. It does this by adding support for remote DAV address books and by adding features to be used along with the Lightning calendar extension. It is a merge of the Lightning Enhancer and the GroupDAV Addressbook Connector.