Some engines and libraries which use OpenAL:

• AgentAE (Linux, Macintosh, Windows)
• C4 Engine (Macintosh, Windows)
• Classical Moon Game Development Kit v18 (Chinese homepage) (Windows)
• Classical Moon Game Development Kit v18 (English Intro) (Windows)
• Decoy3D (Windows)
• Delta3D (Linux, Windows)
• Doom 3 Engine (Windows)
• ELF Integrated Scripting System (Linux, Windows)
• ioquake3    (See also: Wikipedia: Id_Tech_3 )
• Lightweight Java Game Library (Linux, Macintosh, Windows)
• Luxinia (Windows)
• PTK Game Engine (Macintosh, Windows)
• SimGear - Simulator Construction Tools (FreeBSD, Linux, Macintosh, SGI, Windows)
Torque Engine (Linux, Macintosh, Windows)
• Unreal Engine (Linux, Macintosh, Windows)

Language Bindings and Alternative Interfaces to OpenAL:

• Ch (Linux, Macintosh, Windows)
• Delphi Units for OpenAL and some tutorials (Linux, Windows)
• Derelict (D bindings) (Linux, Windows)
• Java Bindings for OpenAL (Linux, Macintosh, Windows)
• .NET Bindings (Linux, Windows)
• OpenALada (Ada bindings) (Windows)
• OpenALXtra (Macromedia Director plugin) (Macintosh, Windows)
• OpenAL++ (Linux, Windows)
• OpenTK (Linux, Windows)
• RockAndRoll (Windows)

Alternative OpenAL Implementations:

• Accelerated ALSA Library for Linux
• Icculus OS X Implementation

OpenAL Tutorials:

• Configuring Surround sound in Linux
• DevMaster.net OpenAL Articles
• edenwaith.com Tutorial
• GameDev -- Programming 3D Sound With OpenAL On Windows
• GameDev -- A Guide To Starting With OpenAL
• GameDev OpenAL Tutorial (Russian)
• Game Programming in C++ From Start to Finish (a section covers OpenAL)
• PDJ OpenAL Tutorial (Brazilian Portuguese)

Suggested Subversion Front-End Software:

• eSvn -- Cross-Platform GUI (Open Source)
• RapidSVN -- Cross-Platform GUI (Open Source)
  
• TortoiseSVN -- Windows (Open Source)
  

Developer Pages (containing OpenAL information):

• Apple Developer Site (Audio page)
• Creative Developer Site (OpenAL page)
• NVIDIA Developer Site (Audio SDK page)