title: is it a good way to change UIViewControllers?
body: <p>I'm new at developing iPhone applications. Application i want to write now is very simple.</p>
  
  <p>I want to have to "screens". For doing this i've created to <code>UIViewController</code> subclasses for both of them. The first one have a button - and when it's pressed i want to change the screen to the second. For doing this i want to send a message to shared <code>AppDelegate</code> object and to change the view in my window. </p>
  
  <p>Maybe it's important:
  The first screen is used for entering ip address of the server i want to connect to. So this screen will appear only once in the application</p>
  
  <p>Am i on the right way ?</p>