GanttProject is a cross-platform desktop tool for project scheduling and management. It runs on Windows, Linux and MacOSX, it is free and its code is opensource.
With GanttProject you can break down your project into a tree of tasks and assign human resources that have to work on each task. You can also establish dependencies between tasks, like "this task can't start until this one is finished".
The PLANdora project was born with the intent of to be a tool to help the software development process, since the customer requirement until the task conclusion, and consequently gather the "history" of project. The PLANdora system can be useful for teams that have problems with resource bottle-necks, parallel projects, critical dead lines, necessity for scope documentation of tasks and requirements, etc.