MKMapViewDelegate.m

#pragma mark -
#pragma mark MKMapViewDelegate

- (void)showDetails:(id)sender
{
    [self.navigationController setToolbarHidden:YES animated:NO];    
	// navigation to detail view
}

- (UIImage *)resizeImage:(UIImage *)flagImage
{
	CGRect resizeRect;            
	resizeRect.size = flagImage.size;
	
	// AnnotationPadding: 10.0f, CalloutHeight:40.0f
	CGSize maxSize = CGRectInset(self.view.bounds,10.0f,10.0f).size;
	maxSize.height -= self.navigationController.navigationBar.frame.size.height + 40.0f;
	
	if (resizeRect.size.width > maxSize.width)
		resizeRect.size = CGSizeMake(maxSize.width, resizeRect.size.height / resizeRect.size.width * maxSize.width);
	if (resizeRect.size.height > maxSize.height)
		resizeRect.size = CGSizeMake(resizeRect.size.width / resizeRect.size.height * maxSize.height, maxSize.height);
	
	resizeRect.origin = (CGPoint){0.0f, 0.0f};
	UIGraphicsBeginImageContext(resizeRect.size);
	[flagImage drawInRect:resizeRect];
	UIImage *resizedImage = UIGraphicsGetImageFromCurrentImageContext();
	UIGraphicsEndImageContext();
	
	return resizedImage;
}

- (MKAnnotationView *)mapView:(MKMapView *)theMapView viewForAnnotation:(id <MKAnnotation>)annotation
{
    // if it's the user location, just return nil.
    if ([annotation isKindOfClass:[MKUserLocation class]])
        return nil;
    
    if ([annotation isKindOfClass:[MyAnnotation class]])
    {
        static NSString* MyIdentifier = @"MyAnnotationIdentifier";
        MKPinAnnotationView* pinView = (MKPinAnnotationView *)[mapView dequeueReusableAnnotationViewWithIdentifier:MyIdentifier];
        if (!pinView)
        {
            MKPinAnnotationView* customPinView = [[[MKPinAnnotationView alloc]
												   initWithAnnotation:annotation reuseIdentifier:MyIdentifier] autorelease];
			
			// ignore the animatesDrop when custom an image
			customPinView.animatesDrop = YES;
            customPinView.pinColor = MKPinAnnotationColorPurple;            
            customPinView.canShowCallout = YES;
            
			// click button in annotation
            UIButton* rightButton = [UIButton buttonWithType:UIButtonTypeDetailDisclosure];
            [rightButton addTarget:self action:@selector(showDetails:) forControlEvents:UIControlEventTouchUpInside];			
            customPinView.rightCalloutAccessoryView = rightButton;
			
			// image for point on map
            UIImage *resizedImage = [self resizeImage:[UIImage imageNamed:@"flag.png"]];                        
            customPinView.image = resizedImage;
            customPinView.opaque = NO;
			
			// image for point in annotation
            UIImageView *sfIconView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"location.png"]];
            customPinView.leftCalloutAccessoryView = sfIconView;
            [sfIconView release];
			
            return customPinView;
        }
        else
        {
            pinView.annotation = annotation;
        }
        return pinView;
    }
    
    return nil;
}

MyAnnotation.m

#import "MyAnnotation.h"

@implementation MyAnnotation


- (id)initWithDict:(NSDictionary *)dict {
	if (self = [super init]) {
		mydict = dict;
	}
	return self;
}

- (CLLocationCoordinate2D)coordinate;
{
    CLLocationCoordinate2D theCoordinate;
    theCoordinate.latitude = [[mydict objectForKey:@"lat"] floatValue];
    theCoordinate.longitude = [[mydict objectForKey:@"lng"] floatValue];
	
    return theCoordinate; 
}

// required if you set the MKPinAnnotationView's "canShowCallout" property to YES
- (NSString *)title
{
    return [mydict objectForKey:@"address"];
}

// optional
- (NSString *)subtitle
{
    return [mydict objectForKey:@"full_name"];
}

- (void)dealloc
{
    [super dealloc];
}

@end

MyAnntation.h

#import <MapKit/MapKit.h>

@interface MyAnnotation : NSObject <MKAnnotation>
{
	NSDictionary *mydict;
}


- (id)initWithDict:(NSDictionary *)dict;

@end