WebCalendar is a PHP-based calendar application that can be configured as a single-user calendar, a multi-user calendar for groups of users, or as an event calendar viewable by visitors. WebCalendar can be setup in a variety of ways, such as...
A schedule management system for a single person
A schedule management system for a group of people, allowing one or more assistants to manage the calendar of another user
An events schedule that anyone can view, allowing visitors to submit new events
A calendar server that can be viewed with iCalendar-compliant calendar applications like Mozilla Sunbird, Apple iCal or GNOME Evolution or RSS-enabled applications like Firefox, Thunderbird, RSSOwl, FeedDemon, or BlogExpress.