A bunch of links regarding sound problems with the STAC9200 chipset on Ubuntu Feisty
Launchpad Bug 117246
No sound - Ubuntu Forums
No sound with hda nvidia and sigmatel stac 9200
Comprehensive sound problems guide
Hda Intel Sound HOWTO
Fedora 6 - No sound on Sigmatel - Gateway laptop
ALSA dmix setup
Envy - nvidia driver download python script