Webical is to be the Squirrelmail of iCalendars. What Squirrelmail is for IMAP, Webical is for iCalendars. This means that support of standards, accessibility and extendability are primary goals.

• iCalendar standard support
• Multiple calendars
• WebDAV support
• CalDAV support in (experimental) plug in
• HTTPS URLs supported (also self signed certificates)
• Plug in architecture (with both back end and front end hooks)
• Authentication configured on container (e.g. Tomcat with database, LDAP, etc.)
• Uses any JDBC database (MySQL, Hypersonic, etc)
• Cross browser support (Firefox, Internet Explorer, Safari, Mobile)
• Section 508 compliant (almost :)

Also check out the screenshots and changelog.