Network Indicator-iPhone

[UIApplication sharedApplication].networkActivityIndicatorVisible = YES;


or custom as

UIActivityIndicatorView *indicator = [[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleWhite];
    indicator.hidesWhenStopped = YES;
    [indicator stopAnimating];
// [indicator startAnimating];
    self.activityIndicator = indicator;
    [indicator release];
   
    UIBarButtonItem *rightButton = [[UIBarButtonItem alloc] initWithCustomView:indicator];
    self.navigationItem.rightBarButtonItem = rightButton;
    [rightButton release];