UIImage category to create a UIImage based on a given UIColor.
I find it especially useful on UIButton states:
UIColor* defaultColor = [UIColor colorWithRed:63.0/255.0
green:114.0/255.0
blue:155.0/255.0
alpha:1.0];
UIColor* depressedColor = [UIColor colorWithRed:85.0/255.0
green:155.0/255.0
blue:210.0/255.0
alpha:1.0];
[self.button setBackgroundImage:[UIImage imageWithColor:defaultColor] forState:UIControlStateNormal];
[self.button setBackgroundImage:[UIImage imageWithColor:depressedColor] forState:UIControlStateHighlighted];
[self.button setBackgroundImage:[UIImage imageWithColor:depressedColor] forState:UIControlStateSelected];