Verified this "STAC9205 Snow&Lion.zip" solution works brilliantly in Snow Leo 10.6.8 on Dell D630. Installed 10.6.0 from upgrade DVD using MyHack 3.1.2 and osxlatitude EDP for D630 on 10.6, then upgraded using combo update 10.6.8, then ran all software updates over network. Still no sound. Tried various solutions both AppleHDA and VooDoo, but the ONLY working solution, and it's a damn good one, is this one I found here. Thanks a million.
Notes on installing these kexts: after 10.6.8 update, delete existing AppleHDA.kext in S/L/E first, then just copy the 4 appropriate kexts from this zip file over to E/E. Then in terminal run:
cd /Extra/Extensions
sudo chown -R root:wheel *
sudo chmod -R 755 *
Finally, run MyHack's "MyFix" in thorough mode on entire drive (" / ")
Reboot and at options, type -f -v
Rock your new audio. Tests good on internal speeks, internal mike, and external speeks through headphone out. Haven't had a chance to try external mike yet. Anyway, this solution is a godsend!