In RSSSampleViewController.m > parseXML the books instructs to set the delegate to self...

[xmlParser setDelegate:self];

Doing so will generate a warning, "Assigning to 'id<NSXMLParserDelegate>' from incompatible type 'RSSSampleViewController *'

To resolve this warning you must declare that you are implementing the NSXMLParserDelegate protocol...

@interface RSSSampleViewController : UIViewController <NSXMLParserDelegate>
...