If you have ever written an iPhone app that requires numeric input, then you surely know about the UIKeyboardTypeNumberPad. And if you have ever used that flavor of the iPhone's keyboard, then you surely know that it lacks one very important feature: The UIKeyboardTypeNumberPad does not have a "return" key.
http://www.neoos.ch/news/46-development/54-uikeyboardtypenumberpad-and-the-missing-return-key