Sunbird Project is a redesign of the Mozilla Calendar component. The goal is to produce a cross platform standalone calendar software based on Mozilla's XUL user interface language. The intended user is someone who uses Mozilla Firefox (or another browser) as his browser, Mozilla Thunderbird (or another mail client) as his mail client and wants a calendar software based on Mozilla.
Sunbird is the new cross-platform calendar software from the Mozilla foundation. It is based around the existing Mozilla Calendar component and is the latest in a string of standalone applications from the foundation, which are gradually replacing the current Mozilla suite of applications. The aim of the project is to create a standalone calendar for someone who uses either Mozilla Thunderbird or Firefox as their email client or browser. Sunbird hopes to offer a reduced footprint and performance enhancement over the original Calendar component. Sunbird is still in the early stages of development and is certainly experimental program with version 0.2 having been released recently. Nonetheless Sunbird is a promising software for those of you already using Thunderbird or Firefox.

The license of this software is Freeware, you can free download and free use this calendar software.