The OpenAL source code is available anonymously through Subversion with an appropriate client.
svn://connect.creativelabs.com/OpenAL
There are various tagged and branched versions of OpenAL available in openal/tags and openal/branches. These are some of the most relevant:
- Linux_Spec1-0 for the last Linux code before the transition towards OpenAL 1.1 began
- MacOSX1-1_Spec1-0 for the last MacOS X code before the transition towards OpenAL 1.1 began
- Win1-1-2_Spec1-0 for the last Windows code before the transition towards OpenAL 1.1 began