Zimbra is an open source server and client technology for next-generation enterprise messaging and collaboration. Please see www.zimbra.com for the latest news and downloads.
The VCS to ICS Calendar Converter allows you to convert VCALENDAR files (for example generated by Nokia nbuexplorer or Microsoft Works) to the newer iCalendar format, used by Android and iOS for example. It allows the parsing of events and todo's.
OpenJean is a cross-platform, extensible, personal information manager. It includes: file manager, RSS aggregator, calendar and appointments diary, mailer, image manager, multimedia manager, favorites, notes, tasks, anniversaries, topics and address book
A multiuser Diary Management System that will enable staff in organisations to set/update/view meetings and appointments. The system will operate via a central server, but clients will able to function offline. It will support Mac OSX/Windows/*nix
CalendarTechnique is a feature rich customizable web calendaring and scheduling application with support for group/shared calendars. CalendarTechnique makes it easy to manage events, tasks and journal entries as well as import and export iCalendar files.
OpenCustomer is a Web-based customer relationship managment (CRM) application, using Mysql and Java/Tomcat. (Online Demo available)
The Mozilla Sunbird Portable Edition project is now part of the PortableApps.com project: http://sourceforge.net/projects/portableapps
The Crosswise project is a web-based community event calendar that adds modular data analysis and visualization, and communication methods, to provide community organizations with a powerful event planning, collaboration and analysis tool.
The lightning-exchange-provider addon allows you to use Microsoft Exchange calendars in Thunderbird, via Exchange’s web services. The addon works on Thunderbird 3.
Spicebird is an open-source email and collaboration suite based on the Mozilla platform. It provides integrated e-mail, contacts, calendaring and instant messaging. It can connect to any SMTP/IMAP email server, CalDav Calendar server and Jabber serve