Gnatter is a site for doing web-based project management. Those of you that are familiar w/ MS Project will feel quite comfortable using Gnatter.
You can manage everything such as: tasks, resources, and calendars. Also, you have the ability to import/export into MS Project.
There is so much that you can do on Gnatter that you really need to see it for yourself. You can link your tasks, create work-flows and charts, etc etc.
For more info click here.