The Freeplane add-on that syncs a GTD mind map with a todo.txt file
TidGi is an privacy-in-mind, automated, auto-git-backup
Freeplane add-on for task management and memo taking
Manage your tasks
A mini todo and project management application
Outlook macros for implementing GTD
The most popular mindmapping and brainstorming software
Yet Another GTD, an opensource GTD
A GTD-inspired ToDo list manager that tells you what to do next!
Cosas is a web emulation of the GTD app Things