Mac OS X

Apple: Mac OS X
The Apple Mac OS X product page. Describes features in the current version of Mac OS X, a screenshot gallery, latest software downloads, and a directory of resources.
http://www.apple.com/macosx/

High Performance Computing on Mac OS X
Collection of tools and information for scientific computation on Mac OS X including Fortran (g77, g95, HPF), MPI, OpenMP, Cactus, Globus, and RNPL among others.
http://hpc.sourceforge.net/

HyperJeff's OS X Page
Features a large list of native OS X software, and essays on software installation.
http://osx.hyperjeff.net/

Mac OS X - Downloads
Directory of freeware, shareware, and commercial software available for download or purchase.
http://www.apple.com/downloads/macosx/

Mac OS X Notes
For OS X users looking to delve into the deeper workings of UNIX. Filled with information on compiling open-source software on OS X (10.2) using the Terminal application.
http://homepage.mac.com/samchops/MACOSX/macosx.html

Mac OS X Security
Security issues and advisories. Locate security vulnerability and published hack reports for the new operating system.
http://www.securemac.com/

Mac OS X Speed FAQ
The speed of the operating system is controlled by several factors. Offers a list and discussion of each.
http://www.macmaps.com/Macosxspeed.html

MacEnterprise.org
(Formerly macosxlabs.org) A community of IT professionals sharing information and solutions to support Macs in an enterprise.
http://www.macenterprise.org/

MacUpdate OSX Software & Games
Directory of OSX freeware, shareware and commercial products.
http://www.macupdate.com/index.php?os=macosx

Max OSX Guru
Tips for tuning and running Darwin and Apple's OSX.
http://www.macosxguru.net/

Modified Oroborus for Mac OS X
Rootless window server to run Linux applications. Includes downloads, version history, and screenshots.
http://oroborosx.sourceforge.net/

OS X for Legacy Macs
Allows the installation of Mac OS X and Darwin on unsupported Macs including the 7300 through 9600 from an unmodified Install CD. Includes a tech support forum and FAQ.
http://eshop.macsales.com/OSXCenter/XPostFacto/

Stepwise
News stories, tutorials, resources for Objective-C programmers using, or wanting to learn more about, Mac OS X's Cocoa environment. Also covers OpenStep and Web Objects programming.
http://www.stepwise.com/

Versiontracker Software Updates
A daily list of updates for Mac OS X software.
http://www.versiontracker.com/macosx/index.shtml