title: Calling a method when UITabBar is selected?
body: <p>I'm currently writing a app on the iPhone and was just wondering if anyone knew a way to call a function but only when a tab is selected.</p>
  
  <p>I have a separate view controller for the tab in question and I want to call a function which updates the GPS position when the tab is selected.</p>
  
  <p>If anyone could help that would be great :)</p>
  
  <p>Thanks
  - James </p>