Refresh of the user current position when the user moves on the route

My code for tracing routes between two points is this开发者_StackOverflow中文版 :

NSString *urlString = [NSString stringWithFormat:@"http://maps.google.com/maps?saddr=%f,%f&daddr=%f,%f&hl=fr&output=mobile&om=5",latUtilisateur,longUtilisateur,latStation,longStation];

the route traced is represented by two points (A and B) and a blue line between it. Now i want to make a kind of a dot point(or what ever) which move instantaneously when the user moves on. Any idea? thanx in advance :)

You can try this tutorial, to help you out:

http://blog.objectgraph.com/index.php/2009/04/08/iphone-sdk-30-playing-with-map-kit-part-3/