Programming ⇝ Programming and APIs

As you can see, both OpenAL and SDL support all major platforms.

OpenAL

Developed by
Creative as a multiplatform positional audio SDK. It is very easy to use.

http://www.openal.org

DirectX
Audio

Supported on
computers running Microsoft Windows only. It has two components - DirectSound
and DirectMusic. DirectSound is older, more archaic, and more low-level,
while DirectMusic is the "way of the future", supporting more
high-level loading and playing of audio files and interactive music. It
is specifically geared toward games, but is useful for any audio application.

http://msdn.microsoft.com/directx/

SDL
Audio

A multiplatform
audio SDK with very basic functionality. It is geared toward playback
more than anything, so don't expect to use it to create a professional
studio recording application.

http://www.libsdl.org/index.php



ASIO

Created by
Steinberg, ASIO is specifically geared toward professional audio applications
and is supported by most major Windows-based multitracking applications,
including Steinberg's own Cubase series.

http://www.libsdl.org/index.php



FMOD

A commercial
multiplatform API. If asked which API was the best, this would be our
answer. The price, however, reflects the quality, although it is more
accessible to non-commercial developers via its freeware licensing.

http://www.fmod.org/

ALSA

The Advanced
Linux Sound Architecture, a sound programming interface for Linux. Although
it is well-written, the documentation is terrible. Your best bet is to
look at some source code.

http://www.alsa-project.org/



OSS

The Open Sound System, used with Linux kernels prior
to 2.6 and on Solaris.

http://www.opensound.com/oss.html

Core Audio

Core Audio is the MacOS audio SDK.

http://www.opensound.com/oss.html

webOS