AppKiDo is a free reference tool for Cocoa Objective-C programmers. The goal of AppKiDo is to help you find what you want in the Cocoa documentation. It does this by parsing the header files and the HTML doc files that were installed with your Developer Tools, and presenting the results in a form that is easy to navigate. AppKiDo can search for names of classes, protocols, functions, types, and constants. Searches are by substring, not keyword. So, for example, if you're wondering how to manage cursors, search for "cursor". Apple has conveniently put the word "cursor" in the names of most things related to cursors.
AppKiDo presents the class hierarchy in a browser view. If you are new to Cocoa, browse the class hierarchy to get acquainted with what's there and how it's organized. If you are more experienced, you can study branches of the hierarchy you never paid attention to before. AppKiDo provides handy "quicklists" of logically related groups of classes. This puts many frequently used classes a click or two away. AppKiDo can display a consolidated list of all methods a class implements, including inherited methods and methods that satisfy a protocol. This can help you understand the complete behavior of a class. Scanning through a consolidated list is more convenient than browsing a class's superclasses and protocols one at a time. AppKiDo can open the .h file for any Cocoa class. Theoretically you shouldn't need to do this, but sometimes it comes in handy.