This kind of chart is an invaluable tool when you have to plan complex projects that must be developed in specific time spans and with clear dependences. You can break down your project into a tree of tasks and assign human resources that have to work on each task, identifying which are the dependencies between tasks, and the time frames for each, deciding which tasks can't start until some other taks is finished.
Quoting from a Project management article,
The project schedule is the core of the project plan. It is used by the project manager to commit people to the project and show the organization how the work will be performed. Schedules are used to communicate final deadlines and, in some cases, to determine resource needs. They are also used as a kind of checklist to make sure that every task necessary is performed. If a task is on the schedule, the team is committed to doing it. In other words, the project schedule is the means by which the project manager brings the team and the project under control.GanttProject renders your project using two charts: Gantt chart for tasks and resource load chart for resources. You may print your charts, generate PDF and HTML reports, exchange data with Microsoft(R) Project(TM) and spreadsheet applications...
This screenshot of the program, lifted from their website, gives an idea of what GanttProject is about —this specific example is a building project:
There is a similar program called Open Workbench, with an impressive feature list. SmartDraw also has a nice feature set for Gantt charts. And you might want to check out other Gantt chart tools for Mac or PC.
If you are a Linux Ubuntu (with KDE desktop, or Kubuntu) you can use KPlato, which is opensource and completely free to use. Its features include:
- Gantt chart with task list and resource allocations per task.
- Resource view with task allocations per resource.
- Accounts view showing planned cost with configurable cut-off date and periodicity.
- Tasks are organized in a work breakdown structure (WBS).
- Resources are organized in a resource breakdown structure (RBS).
- Accounts are organized in a cost breakdown structure (CBS).
- Gantt chart can optionally show:
- Task links (dependencies).
- Task name.
- Allocated resources.
- Float (slack).
- Critical path.
- Critical tasks.
- Progress (% completion).
- Summarytasks, Tasks, and milestones are supported.
- Dialogs to create and edit the project, the different types of tasks, calendars, resources, accounts and progress.
- Task links can be of types: Finish to Start, Finish toFinish or Start to Start. All types can have a time lag defined.
- Different scheduling constraints are supported:
See more details and download the program at the KOffice project page. As you know, there are several ways to install programs in Ubuntu, and it is getting more and more trouble-free every day. Choose what is best for you.
Then there are several online, or web-based, applications for Project Management. Dotproject
is a PHP + MySQL opensource solution, with excellent documentation and online courseware. If you have a Dreamhost hosting account you can install it with their one-click install utility. Super-easy!
More information about Gantt Charts in the Wikipedia article. Also in the Wikipedia, a list of Project management software.