ArduCopter allows you to fly with a computer joystick sending commands via 3DR radio rather than a regular RC system. To use it, you must have the following:

1. Wireless telemetr ardupilot telemetry kit (3DR Radio or Xbee)
2. A USB joystick or Gamepad
3. A laptop computer running the mission planner software

Arducopter has an inexpensiveOSD board called MinimOSD. It reads all the MAVLink data in the APM telemetry stream and overlays it on the video stream if you're using an on-board camera and wireless video transmitter. This is useful if you're flying in First Person View (FPV) mode or don't want to use a laptop at the field to see your telemetry data in the Mission Planner.