Change the font of a UIBarButtonItem

Question

I have a UIBarButtonItem in my UIToolbar titled

Answer 1

These are great answers above. Just updating for iOS7:

NSDictionary *barButtonAppearanceDict = @{NSFontAttributeName : [UIFont fontWithName:@"HelveticaNeue-Thin" size:18.0] , NSForegroundColorAttributeName: [UIColor whiteColor]};
    [[UIBarButtonItem appearance] setTitleTextAttributes:barButtonAppearanceDict forState:UIControlStateNormal];