title: WordPress: get post_parent title
body: <p>I've created a custom sidebar that grabs the post parent's pages:</p>
  
  <pre><code>query_posts("post_type=page&amp;post_parent=6"); 
  </code></pre>
  
  <p>I'd like to grab the title of the post_parent (i.e. "About"). <code>the_title</code> won't work because it's the title of the child pages.</p>
  
  <p>How can I output the post_parent title?</p>