+1  A: 

What is the delegate for the UITextField connected to? Have you made sure that the delegate functions, particularly - (BOOL)textFieldShouldBeginEditing:(UITextField *)textField is returning the right thing (in this case YES)?

Adam Eberbach
The tutorial doesn't ask for a connection to a delegate, just one to an IBOutlet in the view controller. I've run through another tutorial that also has a UITextField without a delegate, simply connected to the view controller's IBOutlet, and that one worked. If it's any help, the tutorial I'm having difficulty with is from "Beginning iPhone 3 Development" by Mark and LaMarche.
Norm
A: 

I am having the same exact problem, with Chapter 4, Controller Fun

Teddy
I "fixed" the problem by starting over, and that second attempt worked. I'm kind of disturbed about that, because without knowing the error, I have no idea what to do if something similar comes up again.
Norm
What do you mean with starting over? Creating the hole nib again or the hole app? I've tried adding UITextFields to other nibs in the app and i have the same problem, the keyboard just doesn't pops up.
sicario
I recreated the entire app, since I had no idea what setting where might have messed things up.
Norm
A: 

Not sure if this is anyone else's problem but I was using a TextField in a TabBar controller displayed modally and I added the shake gesture in my main view controller. This unfortunately meant I was setting [self becomeFirstResponder] in the viewDidLoad. In that case when my modal view displayed it was not becoming the first responder and hence the keyboard did not display.

To fix it I added [self resignFirstResponder] just prior to calling the modal display and all is well once more! Yay (only took five days to figure that out).

JC Software
Didn't work for me :(
sicario