ThinkingRock is a java program which fairly faithfully implements much of the GTD ("Getting Things Done") time/goal management system developed by David Allen.
License: Open Source/CDDL 1.0 --- See the Development Roadmap at the link below. At the bottom of the page you will also find a link to the CDDL license.
Other: See the ThinkingRock forum thread (linked below) discussing previous efforts to implement a portable version of this software.
For more information on GTD see the official website at http://www.davidco.com/