Hi all!
I got this card working with headphone, speaker and mic on 10.6.4 with a few simple steps:
download my files
1, backup your appleHDA.kext, just for safety.
2, remove VoodooHDA.kext
3, copy the AppleHDA.kext to your desktop
4, open it and go here: AppleHDA.kext/Contents/PlugIns/AppleHDAPlatformDriver.kext/Contents/
5, replace the info.plist with which I gave
6, install the AppleHDA.kext and HDAEnabler.kext to S/L/E manually or with a helper app (ie.: kext helper)
it is possible that you can put the HDAEnabler.kext in the Extras/Extensions folder
7, place the AsusK50IN.kext in your Extras/Extensions directory
8, maybe fix your permissions
9, reboot
It worked for me hope it works for you too! Have fun!
MODIFICATION:
ok, i was a bit stupid, I use these kexts with a different kind of laptop and i think the audio driver is for alc662. Sorry. Asus K70IO