This video will demo TrackIR for you, all head movements looking around the cockpit in this video were with TrackIR. Note that it works in three dimensions too, so I could actually have leaned forwards toward my monitor and got closer to the gunsight, or leaned to the side and looked down over the edge of the cockpit if I had felt the need to do so:
Where TrackIR becomes useful in Falcon, (apart from dogfighting obviously) is when you get a SAM launch indication on your F-16's threat display. Being able to look in the direction of the indicated threat with natural head movements means you can pick the missile up visually very quickly. This makes turning in toward the oncoming missile and timing your defensive break to outmaneuever the missile far easier, and much more like how it is done for real. The missiles are fairly deadly in Falcon 4 on realistic settings, but it actually becomes quite an enjoyable challenge dodging them when you can do it this way as opposed to using a 'coolie hat switch' on a joystick to do it. Using a joystick to pan the views can quickly disorientate you and when that happens, the missiles can get you much more easily.
Chock