Apple's developer resource for Mac OS X. Contains guidelines, tutorials and API information for new OS X developers. Most documentation is available in HTML or PDF format.

Apple's guide to porting UNIX software to Mac OS X. Includes information on Mac OS X's quirks and subtle differences.

Tips, tricks, and tutorials for the novice Cocoa developer.

Tutorials, downloads and news for Mac OS X programmers.

A community based Cocoa programming site with content submitted by programmers. Includes tutorials, code, and discussions.

Many articles and books on a broad range of Mac OS X developer topics.

Apple's main AltiVec/Velocity Engine site including an overview, sample code and various software libraries optimized for the G4.

Overview of basic Mac OS X programming resources available from Apple, including links to tutorials, developer tools and libraries, and documentation in PDF and HTML formats.

Big Nerd Ranch offers intensive, head-down Cocoa programming courses taught by experts in a retreat-style environment. Also contains information on Aaron Hillegass' book "Cocoa Programming for Mac OS X".

Open Source frameworks and source code from OmniGroup that extend and enhance Apple's Cocoa APIs, simplifying the addition of common features such as find and replace and preference management. OmniGroup also provides advanced networking and HTML parsing frameworks.

Perl development environment for OS X. Features include debugging, executiing Perl Scripts, and installing modules. Offers downloads and registration.

Cross development tools for OS X. Toolchains, USB, downloads, links, and forum.