FreeMiCal allows the bulk export of MS Outlook appointment items to RFC 2445 conformant iCal format. .NET 2.0 or greater and Outlook 2003 or 2007 Interop Services required.
CentraView - Browser based Enterprise Java (J2EE) Contact Management, Groupware, Collaboration, CRM, SFA, Project Management software. Run locally or as a hosted service. Built on Apache Tomcat, JBoss, MySQL, Linux (Fedora, RedHat and others) & Windows
Appointment scheduler allows a customer, patient or client to schedule an appointment via the company's homepage. This project is developed on java platform. and this is totally free.
An open source personal organizer ala "Daytimers"