title: Regular Expression To get the string of a Youtube Video
body: <p>I want to download a youtube video from a link say:</p>
  
  <p><a href="http://www.youtube.com/watch?v=j5-yKhDd64s" rel="nofollow">http://www.youtube.com/watch?v=j5-yKhDd64s</a></p>
  
  <p>How to get the mp4 version of this flash video using regular expression, with Objective-c?
  Please point me to some sample code.</p>