Since I personally have not been able to locate this information anywhere, I have created a wiki page to log the testing and experimentation I have been doing with sound. Please ignore if this is duplicate information.
Currently info only for Headless and ALIP linaro images, but I plan on adding netbook. Any additional pointers would be greatly appreciated.
https://wiki.linaro.org/KurtTaylor/BeagleBoardSound
Regards,
Kurt Taylor (krtaylor irc)