From the ALSA wiki
Advanced Linux Sound Architecture
This is an unofficial Wiki about the freely available ALSA sound architecture which provides low level Audio and MIDI functionality to the Linux operating system. Read the introduction and about page for more information about this site and visit the official ALSA Project site for additional information.
An alphabetically sorted list of all available drivers.
Issues dealing with installing and setting up ALSA for the first time.
Operational usage notes for ALSA, tools, utilities and applications.
How to compile ALSA from source code and documentation for developers.
Help when dealing with ALSA problems.
Links to offsite documentation and specialized Linux distributions.