iDevGames

Macintosh game development website featuring news, tutorials, game assets, forums and articles.
http://www.idevgames.com/

MacHack

"The Annual Conference for Leading Edge Developers"; a multi-day round-the-clock ritual involving gallons of soda, heinous hacks, and lots of camaraderie. Not to be missed!
http://www.machack.com/

Macdev at MIT

Various resources for Macintosh development from the folks over at MIT.
http://web.mit.edu/macdev/

Sound & Vision, Inc.

Develop software for Macintosh platform. On this site users can find information about FineReader 5 Pro, development and layout software.
http://www.softformac.com/

GNUstep Project

A project devoted to providing an object oriented application framework to developers.
http://www.gnustep.org/

MacOS Web Directory

A directory of Mac programming related sites, including development kits, format specs, toolkits, open source, tutorials, and webzines.
http://www.strout.net/macweb.cgi?dir=/Programming

Dr. Dobb's - The Fifth Column

Good general resource including Michael Swaine's subversive perspective on the world of Macintosh development updated each month. Offers source code, online search, and book reviews.
http://www.ddj.com/columns/fifth/

Apple Developer Connection

Provides news and technical information for Apple Developers.
http://developer.apple.com/

Mac OS 8 and 9 Developer Documentation

Gateway to Apple's documentation for programming Mac OS 8 and 9, including Carbon development.
http://developer.apple.com/macos/