Mozilla Sunbird

Mozilla Sunbird is a free, open source, cross-platform calendar application developed by the Mozilla Foundation and many volunteers.[3] Announced in July 2003[4], Sunbird is a standalone version of the now discontinued Mozilla Calendar Extension.
It is currently developed as a standalone version of the Lightning extension for Mozilla Thunderbird that provides a calendar to the mail management application.

Versions:
The latest version is 0.7[5]. Version 0.3 of Sunbird, and its "sister project", Lightning, were scheduled to be released simultaneously in late September 2006[6], but a release candidate was not made until October.[7] Mozilla Sunbird is described as "...a cross platform standalone calendar application based on Mozilla's XUL user interface language."[8] Version 0.3 of Sunbird is also available in a portable version [9].
Version 0.5 was released June 27, 2007[10] and includes support for Google Calendar via an extension[11].

Sun contributions:
Sun Microsystems has been contributing significantly to the Lightning extension project [12] to provide users with an alternative free and open source choice to Microsoft Office by combining OpenOffice.org and Thunderbird/Lightning. Sun's key focus areas in addition to general bug fixing are calendar views, team/collaboration features and support for the Sun Java System Calendar Server [13]. Since both projects share the same code base, any contribution to one of them is a direct contribution to the other.

Mozilla Calendar Project:
The project started with a single extension for the Mozilla projects known as Mozilla Calendar. It was a free software / open source calendar and personal information manager based on the open iCalendar standard. It was developed as part of the Mozilla project. Now, Mozilla Sunbird and the Lightning project have replaced the Mozilla Calendar. As with other Mozilla projects, Mozilla Calendar was cross-platform, and used the XUL user interface language. It worked with Microsoft Windows, Linux, Mac OS X, and FreeBSD.
The Mozilla Calendar project was announced by the Mozilla Organization (now the Mozilla Foundation) in October 2001. The original code, used by Mozilla Calendar and now the Mozilla Sunbird, was donated by OEone (now Axentra),[1] who had developed it for use in their Mozilla-based HomeBase DESKTOP system. The project was initially led by OEone employee Mike Potter. Shortly after Mike Potter and his team had to pull out of development due to other projects taking precedence[2], Mostafa Hosseini was announced as the new project lead.[3]
The initial plan was for Mozilla Calendar to eventually be integrated into the Mozilla Application Suite alongside the other components. However, this plan was dropped when Mozilla decided to focus on its nascent standalone applications rather than the integrated suite.
Mozilla Calendar could be installed as a component in the Mozilla Application Suite, or as an extension in either the Mozilla Firefox standalone browser or the Mozilla Thunderbird standalone mail and newsgroups client. The extension has now been replaced by the Lightning project, a project with similar features, but with tighter integration with Thunderbird.

Download Mozilla Sunbird from this link

Source:http://en.wikipedia.org/wiki/Mozilla_Sunbird