You can also assign it a date to be due. Tabs at the bottom of the screen allow you to switch between All, Done or To Be Done pages. You can also sort by date by tapping on the date column. Unfortunately, when a task is overdue, it isn't marked in such a way as to get your attention. This application is also pretty much the same as that on the PalmPilot.
Planner is the datebook application.
This is where you add your meetings and events that you need to be reminded of. Alarms can be set for each event. The Planner application has four different views. A daily view will list your events for a specific day. It also has a time bar at the top of the display that is broken up into squares that are equal to 30min intervals.