Applications which run on mobile devices have special user interface requirements. I think Apple did a great job introducing innovative controls on the iPhone/iPod touch platfor
I personally would recommend mirabyte's Touch Controls Suite 2. The new version 2 is much better than the first release (great performance, low memory consumtion) and they have probably the best value for money. I used them in some client projects and I'm very pleased with them, also because of the very active community in their support forums that helped me a lot!