Awesome

MHTintHelper

Picking the right tintColor for your navigation bars and toolbars can be tricky. This class adds a temporary view with three sliders to your app. You can use it to quickly play with the tint colors until you find one that suits your color scheme.

Screenshot

To use:

#import "MHTintHelper.h"

- (void)viewDidLoad
{
    [super viewDidLoad];
    [MHTintHelper showInView:self.view forItem:self.navigationBar];
}

Requires at least iOS 5 and ARC.