How to reverse geocode an annotation?

Question

I have an app that drops multiple annotations, and I want to reverse geocode the pin locations and set the address as the subtitle. Here is the code I have so far, but I do not know how to implement the reverse geocoder.

-(void)press:(UILongPressGestureRecognizer *)recognizer
{
    CGPoint touchPoint = [recognizer locationInView:worldView];
    CLLocationCoordinate2D touchMapCoordinate = [worldView convertPoint:touchPoint toCoordinateFromView:worldView];

    if (UIGestureRecognizerStateBegan == [recognizer state]) {
        MapPoint *mp = [[MapPoint alloc]initWithCoordinate:touchMapCoordinate
                                                 title:@"Dream House"];
        [worldView addAnnotation:mp];

        geocoder = [[CLGeocoder alloc]init];

        CLLocation *location = [[CLLocation alloc]initWithCoordinate:touchMapCoordinate
                                                        altitude:CLLocationDistanceMax
                                              horizontalAccuracy:kCLLocationAccuracyBest
                                                verticalAccuracy:kCLLocationAccuracyBest
                                                       timestamp:[NSDate date]];

        [geocoder reverseGeocodeLocation:location
                   completionHandler:^(NSArray *placemarks, NSError *error) {
                       <#code#>
                   }];

    }
}

The pins would be dropped on homes, so I just want to show the house address. Thanks for the help.