I'm able to change the text color of UIBarButtonItem using this code snippet (iOS 5+):
NSMutableDictionary *attributes = [NSMutableDictionary dictionary];
[attributes setValue:[UIColor blackColor] forKey:UITextAttributeTextColor];
[[UIBarButtonItem appearance] setTitleTextAttributes:attributes forState:UIControlStateNormal];
Unfortunately this does not affect UIBarButtonSystemItemAdd.
Is there a way to change the text color of the UIBarButtonSystemItemAdd ?