Hi.
I am working on in-app purchase. In my application we added the following code in appdelegate:
    #import "InappPurchaseAppDelegate.h"
    #import "MainController.h"
    #import "MKStoreManager.h"
    #import "MKStoreObserver.h"
    @implementation InappPurchaseAppDelegate
    @synthesize window;
    - (void)applicationDidFinishLaunching:(UIApplication *)application 
    { 
      [MKStoreManager sharedManager];
      navigationController = [[UINavigationController alloc] init];
      [window addSubview:navigationController.view];
      MainController *frontController =[[MainController alloc] init];
      [navigationController pushViewController:frontController animated:NO ];
      [frontController release];    // Override point for customization after      application launch
      [window makeKeyAndVisible];
    }
and added the following code in our controller:
    #import "MainController.h"
    #import "MKStoreManager.h"
    #import "MKStoreObserver.h"
    #import "InappPurchaseAppDelegate.h"
    @implementation MainController
    -(IBAction)InappPurchase:(id)sender
    {
      [[MKStoreManager sharedManager] buyFeatureA];
    }
I also added storekit framework but when the button is clicked nothing happens.