Active Calendar is a PHP class that generates calendars (month or year view) as HTML tables (XHTML-Valid). It can produce static calendars without any links or calendars with navigation controls, a date picker control, event days and content with event URLs, and linkable days (optionally URL or Javascript). The layout can be configured using CSS, and JavaScript is not required. The supported dates (on systems using a 32-bit signed integer Unix time_t) are: 1902-2037 (Unix) and 1971-2037 (Windows), when using the default PHP native date functions, and 100-3000 and later, when using the ADOdb Date Library.
License: LGPL
More details (source code, documentation, examples etc.) at: http://freshmeat.net/projects/activecalendar/