A way to make any object to "shake". In this example we use a UILabel.

ShakeAnimation

UILabel *myLabel....    

CABasicAnimation *shake = [CABasicAnimation animationWithKeyPath:@"position"];
    [shake setDuration:0.1];
    [shake setRepeatCount:2];
    [shake setAutoreverses:YES];
    [shake setFromValue:[NSValue valueWithCGPoint:
                         CGPointMake(myLabel.center.x - 5,myLabel.center.y)]];
    [shake setToValue:[NSValue valueWithCGPoint:
                       CGPointMake(myLabel.center.x + 5, myLabel.center.y)]];
    [myLabel.layer addAnimation:shake forKey:@"position"];