iOS/Web: Most to-do list apps worth their salt have the ability to schedule tasks. TeamWeek takes it a step further by creating Gantt charts to see how long each task will take and who is responsible for what.
We've talked before about how to use Gantt charts to do things like plan your holiday cooking. TeamWeek features a dead-simple interface available on the web and iPad, with an Android app on the way soon. The service is free for teams with up to five members.