How to change MKMapView's user-location blue dot to an image of choice?

Is it possible to change the blue dot which indicates the user's location in MKMapView to an image? For example a little car or any .png image?

In the viewForAnnotation: method of MKMapViewDelegate probably you would be having the code like this.

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

    if (annotation == mapView.userLocation) return nil;
    ...

We return nil if the annotation is userLocation to let the mapView display the blue dot & circle animation. In order to show our custom annotation for userLocation just remove the line return nil; and do your customization there.

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

    static NSString* AnnotationIdentifier = @"Annotation";
    MKPinAnnotationView *pinView = (MKPinAnnotationView *)[mapView dequeueReusableAnnotationViewWithIdentifier:AnnotationIdentifier];

    if (!pinView) {

        MKPinAnnotationView *customPinView = [[[MKPinAnnotationView alloc] initWithAnnotation:annotation reuseIdentifier:AnnotationIdentifier] autorelease];   
        if (annotation == mapView.userLocation){
           customPinView.image = [UIImage imageNamed:@"myCarImage.png"];
        }
        else{
            customPinView.image = [UIImage imageNamed:@"mySomeOtherImage.png"];
        }
        customPinView.animatesDrop = NO;
        customPinView.canShowCallout = YES;
        return customPinView;

    } else {

        pinView.annotation = annotation;
    }

    return pinView;
}