title: iPhone MapKit: select location (coordinates) manually by touching MKMapView
body: <p>I would like to offer the user the possibility to (manually) select lat. and long. coordinates by touching a <code>MKMapView</code>. How can I achieve that?</p>
  
  <p>I've seen that the <code>MKMapView</code> delegate offers the method <code>convertPoint:toCoordinateFromView:</code> . I think, that could be a good starting, but I don't know how to create a point from a touch action.</p>
  
  <p>I would appreciate any help. Thanks.</p>