The iPhone Compass App
The Compass app on your iPhone works like a magnetic needle compass. Launch the Compass app by tapping its icon in the Utilities folder on the second Home screen. You see the direction you’re facing.
But wait — there’s more. If you were to tap the little arrowhead icon in the lower-left corner of the Compass screen, the Maps app launches. Now for the cool part: Tap the little arrowhead icon in the lower-left corner of the Maps app two times and the blue marker grows a little white cone that indicates the direction you’re facing.
Also note that when the map is in compass mode, the little arrowhead icon in its lower-left corner grows a little white cone as well, letting you know that you’re now using the compass mode.
If you rotate to face a different direction while Maps is in compass mode, the map rotates in real time. So the map always displays the direction you’re currently facing, even if you’ve moved around a bit, which is pretty darn cool.