It seems like over the past year and a half many people have had a lot of trouble finding a USB-audio adapter that works with this project.
If you have one that works, please post the specific model # here along with any other helpful notes (ie. had to install kmod-alsa, change sampling rates, etc.).
I'll start:SYBA SD-CM-UAUD
source: $10 @ Newegg.com in the USA