From MozillaZine Knowledge Base

I want the same functionality as in Outlook. A calendar loaded automatically. Can it be done?

There are two calendars available for the Mozilla Suite - Calendar and Sunbird.

Sunbird is a stand alone Calendar - not integrated with the Mozilla Suite. To load Sunbird ans tire it in tray - check here:

SunTray

The Calendar is an extension, presently at version 0.8. A tighter integration is planned for the 1.0 release.