High-Level Language Parsing via Objective-C

URLCache subclass with on-disk cache support on iPhone/iPad

AFNetworking is a delightful networking library for iOS and Mac OS X. It's built on top of familiar Foundation network classes, using NSOperation for scheduling and concurrency, and blocks for convenience and flexibility. It's designed to make common tasks easy, and to make complex tasks simple.

MapKit for Mac is a framework for displaying maps in a Cocoa application that is API-compatible with Apple's MapKit framework for iOS.

Custom UI Component Database for iOS and Mac OS X

OCMock is an Objective-C implementation of mock objects

BWToolkit is an Interface Builder plugin that contains commonly used UI elements and other objects designed to simplify Mac development. XCode 3

Technical Note TN2124

"Objective-C is really easy. The language was never a problem. You know what was? Cocoa. Learning the differences between layer-backed views, layer-hosted views — understanding that you have to subclass everything — balancing delegates, weak connections, strong connections, KVC, view controllers, and notifications — understanding little intricacies like how AppKit flips .xibs when it load them up or how hard it is to make one word in a sentence bold. I’m not going to lie: Cocoa (that is: AppKit, UIKit, Core Text, Core Animation, etc) is extremely difficult. The gap between simple example apps and a fully functional application is huge.

Projects like Chameleon that give you a purely layer-backed environment to work with using a modern API (UIKit) matter far more than the language you’re using. This isn’t to say MacRuby isn’t awesome — it just means that it doesn’t make AppKit development any easier; you still have to learn Cocoa.

Along those same lines, I think that Cocoa is dying for a framework. Something that weighs on the simple defaults side rather than complex code generation side."