title: How to set content-type when using initWithContentsOfUrl
body: <p>Basically I want to set </p>
  
  <p>Content-Type: application/json;</p>
  
  <p>in order to call a dot net web service and have it return json to an iphone application.</p>
  
  <p>At the moment I have</p>
  
  <pre>
  NSString * jsonres = [[NSString alloc] initWithContentsOfURL:url];
  </pre>
  
  <p>What do I need instead in order to issue a blocking request ?</p>