FullCalendar is a jQuery plugin that provides a full-sized, drag & drop calendar. It uses AJAX to fetch events on-the-fly for each month and can be easily configured to use your own feed format (an extension is provided for Google Calendar). It is visually customizable and exposes hooks for user-triggered events (like clicking or dragging an event).
FullCalendar is cross-browser component that has been tested on Firefox 3, Safari 3, Opera 9, IE 6/7. It is very well documented allowing you to extend it further for your own specific needs. Download includes a basic stylesheet, the Google Calendar extension, and the necessary jQuery and jQuery UI files. The jQuery UI files (ui.core.js, ui.draggable.js) are only necessary if you plan to do drag & drop.
Developed by Adam Shaw; FullCalendar jQuery Pluginis available for download under GPL & MIT license. You can find further information, demo & download on Adam Shaw’s Website.