bobbyd's install works as far as getting audio output goes. There are no options whatsoever for input/microphones. VoodooHDA seems to work a little bit better. I'm using 0.2.2b from their official forums, and it still doesn't give me microphone support, but I can get my guitar to work that I'm using through line-in. I'm using 32-bit 10.6.3 on a Rev.1, by the way.

I'm really miffed that Apple managed to break kext support for a lot of older kexts. Under 10.6.2 I had everything working, Mic+Speakers+Line-in. I'm considering swapping motherboards to have something that works. :/