Custom UITabBar

Technique 1:
http://blog.theanalogguy.be/2010/10/06/custom-colored-uitabbar-icons/

Technique 2:

@implementation UITabBar (CustomImage)
- (void)drawRect:(CGRect)rect {
    UIImage *image = [UIImage imageNamed: @"background.png"];
    [image drawInRect:CGRectMake(0, 0, self.frame.size.width, self.frame.size.height)];
}
@end

http://stackoverflow.com/questions/675433/custom-colors-in-uitabbar

Technique 3
http://idevrecipes.com/2011/01/04/how-does-the-twitter-iphone-app-implement-a-custom-tab-bar/

Technique 4: (Tried and tested)
https://github.com/rumex/RXCustomTabBar