title: iPhone parsing url for GET params
body: <p>I have an string which is got from parsing an xml site.</p>
  
  <pre><code>http://www.arijasoft.com/givemesomthing.php?a=3434&amp;amp;b=435edsf&amp;amp;c=500
  </code></pre>
  
  <p>I want to have an NSString function that will be able to parse the value of c.
  Is there a default function or do i have to write it manually.</p>