FET is a free timetabling program for automatically generating the timetable of a school, high-school or university. It is licensed under GNU/GPL (free software, open source).
Intime is a program for editing school timetables. It has a graphical user interface and does not support automatic timetable creation. It is in early alpha stage, but is quite stable. Unfortunately it does not seem to be actively developed anymore.
Planner is a tool for planning, scheduling and tracking projects. Planner is an open source project targetting the GNOME Desktop. The project is run by Imendio, who develops the software in cooperation with the Planner community.
SchoolTool is a project to develop a common global school administration infrastructure that is freely available under an Open Source licence.
GNUTU (Student's Schedule) is designed for students from primary and secondary schools - using it, you can note various information (like marks, tests' dates and important school events). It also can create various statistics, search for all entered data, calculate your average; it can also serve as a diary and much more. Application works in Linux and Windows operating systems.
The Swing Timetable Platform
Open Course Timetabler is free and open source application for university and school course timetabling. It is written in C# and runs under .NET framework on Windows (and will likely run under Mono on Linux or Mac OS X).
University Course Timetabling & Student Sectioning Application
GAUL is an open source programming library, released under the GNU General Public License. It is designed to assist in the development of code that requires evolutionary algorithms.
G-Tablix is (to be) a graphical user interface to Tablix, written with perl-gtk2. It helps you prepare a proper configuration file and is able to run Tablix and plot the convergence graphs also.
Java based GUI for Tablix.
TTML is a proposed standard mark up language for describing general timetabling problems. It is quite different from the XML based format Tablix uses. See also TTML support.
Absolutely indispensable tool when installing Tablix on clusters of machines.
Detailed instructions on how to get PVM3 running under Cygwin on Microsoft Windows.