title: Equivalent method for addChildViewController for iOS 4.0
body: <p>Is there an equivalent method for <code>addChildViewController</code> for iOS 4.0 and later?</p>
  
  <p>edit : addChildViewController is only available for ios 5.0 an later
  What i need to do : I have a view controller (A), that acts like a container. And I need to add a view controller as child of A.</p>