MKMapView - Custom View for Annotation

First step is to have MKMapView delegate set and override the viewForAnnotation method 

Next is to create annotation 

thePlane = [[MKPointAnnotation alloc] init];

    thePlane.coordinate = startPoint;

    thePlane.title = @"Agent";

    [self.mapView addAnnotation:thePlane];

- (MKAnnotationView *)mapView:(MKMapView *)theMapView viewForAnnotation:(id <MKAnnotation>)annotation

{

    static NSString *SFAnnotationIdentifier = @"AnnotationIdentifier";

    MKPinAnnotationView *pinView =

    (MKPinAnnotationView *)[self.mapView dequeueReusableAnnotationViewWithIdentifier:SFAnnotationIdentifier];

    if (!pinView)

    {

        MKAnnotationView *annotationView = [[MKAnnotationView alloc] initWithAnnotation:annotation

                                                                         reuseIdentifier:SFAnnotationIdentifier];

        UIImage *flagImage = [UIImage imageNamed:@"car.png"];

        annotationView.centerOffset = CGPointMake(0, -16);

        // You may need to resize the image here.

        annotationView.image = flagImage;

        return annotationView;

    }

    else

    {

        pinView.annotation = annotation;

    }

    return pinView;

}

references:

https://gist.github.com/siqin/3175036