Task Coach
http://www.taskcoach.org/

Task Coach is a simple open source todo manager to manage personal tasks and todo lists. It grew out of frustration that well-known task managers, such as those provided with Outlook or Lotus Notes, do not provide facilities for composite tasks. Often, tasks and other things todo consist of several activities. Task Coach is designed to deal with composite tasks. Task Coach is developed by Frank Niessink and Jerome Laheurte, with help of different people providing translations. Currently, Task Coach is at version 0.66.2 . This has been added to the tools section of Research Resources Subject Tracer™ Information Blog.