title: how can I show compass/heading on mapkit mapview
body: <p>on the iPhone 3GS in the "Maps" app you can click the icon which usually shows your position twice and the blue dot gains what looks like a beam from a headlamp, basically showing you the direction you are facing on the map and rotating the image accordingly. </p>
  
  <p>Is this option available using MapKit MapView ?</p>
  
  <p>I'm know that I can get my heading with something like</p>
  
  <pre><code>- (void)locationManager:(CLLocationManager *) manager didUpdateHeading:(CLHeading *) newHeading {
  </code></pre>
  
  <p>// If the accuracy is valid, process the event.</p>
  
  <pre><code>if (newHeading.headingAccuracy &gt; 0) {
  
      CLLocationDirection theHeading = newHeading.magneticHeading;
      ...
  }
  </code></pre>
  
  <p>}</p>
  
  <p>but I don't know how to get that nice headlamp effect in Mapkit and there doesn't seem to be any documentation. </p>
  
  <p>Any ideas?</p>