And again Game Center module.

- (void)showLeaderboard  
{  
    if(!isAuthenticated) 
    {
        return;  
    }
    
    GKLeaderboardViewController *leaderboardController = [[GKLeaderboardViewController alloc] init];   
    
    if (leaderboardController != nil) {  
        leaderboardController.leaderboardDelegate = self;  
          
        [app->appDelegate.view addSubview: gameCenterViewController.view];  
        [gameCenterViewController presentModalViewController: leaderboardController animated: YES];  
        isViewOpened = YES;
    }     
}  
  
- (void)leaderboardViewControllerDidFinish:(GKLeaderboardViewController *)viewController  
{  
    [gameCenterViewController dismissModalViewControllerAnimated:YES];  
    [viewController.view.superview removeFromSuperview];  
    [viewController release];  
    isViewOpened = NO;
} 

Function IsGameCenterAvailable:Bool()
Function InitializeGameCenter:Void()   
Function ReInitGameCenter:Void()
Function IsPlayerAvailable:Bool()

Function SendScore:Void(scScore%, scCategory$)
Function SendAchievement:Void(scAchName$, scPercent#)

Function OpenLeaderBoard:Void()
Function OpenAchievements:Void()

Function DeInitGameCenter:Void()

Function IsGameCenterVisible:Bool() 'useful for disable taps affect on what's under the Leaderboard or Archievements window.