title: NSDateFormatter returning nil in OS 4.0
body: <p>I had the following code working on on OS 3.x</p>
  
  <pre><code>NSString *stringDate = @"2010-06-21T20:06:36+00:00";
  NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
  [dateFormatter setDateFormat:@"yyyy-MM-dd'T'HH:mm:ssZ"];
  NSDate *theDate = [dateFormatter dateFromString:stringDate];
  NSLog(@"%@",[dateFormatter stringFromDate:theDate]);
  </code></pre>
  
  <p>but now in the newest xcode 3.2.3 under the iOS4 simulator, the varialble theDate is nil.</p>
  
  <p>I have looked through the class reference and do not see anything deprecated or implemented differently for iOS4 with these specific methods. What did i leave out?</p>