Cocoa

The Objective-C environment that pervades Mac OS X and iOS

• AFNetworking - a networking library
• Cocoa Controls - a public library of useful controls for your desktop and mobile apps
• nib2objc - a utility to transform NIB files into Objective-C code
• JSCocoa - a JavaScript bridge that works like PyObjC
• BMScript - an easy way to invoke scripting languages via NSTask
• RestKit - a REST framework that does all the dirty work for you.
• RegexKit, a Cocoa wrapper for PCRE.
• Getting Started with Cocoa: a Friendlier Approach - a step-by-step guide with online references
• Connection Kit, a multi-protocol file transfer framework that supports HTTP, FTP, WebDAV and a number of other niceties.
• Cocotron, a Windows and Linux (partial) port, not unlike GNUstep.
• iLife Controls - use iLife-like UI elements in your applications.
• Cocoalab freebies - including a “Learn Objective-C with Xcode” e-book.
• OpenGL Screensaver Sample
• Registering Protocol Handlers
• Customizing the Cocoa Text System
• PSMTabBarControl - drop-in for Interface Builder, with source.