A project management system manages project schedule data using separate current and historical task schedule data structures. In general, current schedule data is stored separately from historical schedule data, so that the current schedule data may be retrieved separately from the historical task schedule data. The project management system may also maintain unscheduled tasks as “to-do lists.” Tasks may be added to a member's schedule without specifying any planned dates and the tasks are added to the database. The tasks have an associated revision number of 0 to indicate that the tasks were added, but not yet scheduled. The tasks are displayed in the member schedule editor and in Web page schedules. The tasks may then be displayed in the member schedule editor and in Web page schedules in a manner that allows a user to readily determine that the tasks are “to-do list” tasks.