It's a thin alien wrapper around the C interface and was pretty easy to write given Factor's great C FFI support (called 'alien'). It has been tested under Windows and Linux and should be easy to get going for the Mac.
You'll need to install OpenAL and ALUT. Binaries for these are available from the OpenAL download page. With Ubuntu Linux you can install these libraries with:
apt-get install libopenal-dev libalut-dev
Note that you need the 'dev' versions for Factor to find the shared libraries.
Under Windows make sure you put the alut.dll file somewhere in your path. To test it from within Factor:
"libs/openal" require USE: openal play-hello
This should play the default 'Hello World' example. I want to use this to add sound to my Space Invaders emulator.