UIScrollView - showing the scroll bar

No, you can't make them always show, but you can make them temporarily flash.

[myScrollView flashScrollIndicators];

They are scroll indicators, not scroll bars. You can't use them to scroll.

my solution for show scroll indicators all the time

#define noDisableVerticalScrollTag 836913
#define noDisableHorizontalScrollTag 836914

@implementation UIImageView (ForScrollView)

- (void) setAlpha:(float)alpha {

if (self.superview.tag == noDisableVerticalScrollTag) {
    if (alpha == 0 && self.autoresizingMask == UIViewAutoresizingFlexibleLeftMargin) {
        if (self.frame.size.width < 10 && self.frame.size.height > self.frame.size.width) {
            UIScrollView *sc = (UIScrollView*)self.superview;
            if (sc.frame.size.height < sc.contentSize.height) {
                return;
            }
        }
    }
}

if (self.superview.tag == noDisableHorizontalScrollTag) {
    if (alpha == 0 && self.autoresizingMask == UIViewAutoresizingFlexibleTopMargin) {
        if (self.frame.size.height < 10 && self.frame.size.height < self.frame.size.width) {
            UIScrollView *sc = (UIScrollView*)self.superview;
            if (sc.frame.size.width < sc.contentSize.width) {
                return;
            }
        }
    }
}

[super setAlpha:alpha];
}
@end

UPDATE: This solution cause some issues on 64-bit. For more detail look here

As far as I know, this isn't possible. The only API call which controls displaying the scroll indicator is showsVerticalScrollIndicator and that can only disable displaying the indicator altogether.

You could flashScrollIndicators when the view appears so that the user knows where in the scroll view they are.