Great little rundown on the UITextField API. Very helpful!
UITextField – A Complete API Overview | iPhone Programming Tutorials
The UITextField is probably one of the most commonly used UI controls on the iPhone. It is the primary method of user input via the keyboard and provides a great deal of additional functionality. With the success of our las API tutorial on NSArray, I thought I would do another walkthrough, this time on UITextField. I will be explaining all of the properties for it as well as bringing up some functionality that you may not have known about.