title: Is it possible to check if a user has a twitter account in the built-in twitter app of iOS 5?
body: <p>iOS 5 has deep twitter integration. How can I check if the user has an account in the built-in twitter app (meaning he uses it), and then do a <code>UIApplication openURL:</code> to trigger following a user or pre-composing a tweet?</p>
  
  <blockquote>
    <p>One of the new features for developers in the iOS 5 SDK is support for
    the Twitter API. Apple has made it easy for developers to add Twitter
    support to their apps and to allow users to easily control whether or
    not an app has access to post to their Twitter account.</p>
  </blockquote>
  
  <p>According to <a href="http://mashable.com/2011/10/12/twitter-ios-5-integration/" rel="nofollow">this site</a> it is possible. How's that Twitter Framework called?</p>