Apple Developer Connection: Darwin Releases
- Official page with downloads of the various Darwin releases and developer tools.
- http://www.opensource.apple.com/darwinsource/

Darwin Developer Documentation
- Programming in the Darwin kernel and information on the differences between Darwin and other BSDs.
- http://developer.apple.com/documentation/Darwin/Darwin.html

Getting Started With Darwin/x86
- A helpful guide to getting and installing Darwin on an x86 system.
- http://darwin.monkeyvoodoo.net/

The GNU-Darwin Distribution
- A Unix distribution which focuses on the porting of free software to Darwin and Mac OS X.
- http://www.gnu-darwin.org/

The Challenges of Integrating the Unix and Mac OS Environments
- A paper on the design issues Apple faced when they ported the Mac OS to a semantically different Unix base (Darwin).
- http://www.mit.edu/people/wsanchez/papers/USENIX_2000/

Hexley the Platypus
- The mascot of the Darwin OS.
- http://www.hexley.com/

XDarwin: X Windows on Darwin and Mac OS X
- A general overview of the project to bring XFree86 (X11 server) to Darwin and Mac OS X as well as pointers to download and mirror sites.
- http://www.xdarwin.org/

Fink
- A package manager for Darwin based on the Debian apt-get set of tools. 2900+ ports listed.
- http://fink.sourceforge.net/

Open Software in a Commercial Operating System
- A paper written by Wilfredo Sánchez, the then Open Source Engineering Lead at Apple, about the use of open source in commercial software such as Mac OS X Server.
- http://www.mit.edu/people/wsanchez/papers/FREENIX99.html