Mozilla Calendar is a small plugin for the three Mozilla products, Mozilla Firefox, Mozilla Thunderbird and the Mozilla Application suite.

Once installed, you have access to a fully functional calendar from within whichever application you chose to install it into.

It has support for multiple calendars, so you can have different calendars for work and home, or for different members of a household.

You can choose between a daily, weekly or monthly view, and assign calendar entries to different categories for easy searching. Reminder alarms can be set for all entries, or to recur at user-specified intervals.

A neat feature is the Remote Calendar option which lets you publish and share your calendars with other people via an FTP server or webDAV enabled web server.

There is also a Tasks section where you can keep track of all those things you have to do.