I just installed Ubuntu 12.04 on a Macbook pro from early 2008 (Santa Rosa model). Everything works fine on the computer so far except sound. I'm new to Ubuntu, but I've attempted to manually specify module parameters as outlined here, and either I did something incorrectly or that didn't solve the problem. The card is a Realtek ALC 889A, and I know from previous installations of Windows that it uses Realtek HD Audio as a separate process there (rather than being integrated into the OS).
I'm sure this is entry level stuff, but all the guides I've found haven't been very clear or addressed a different problem (fuzzy sound, speaker pops, etc).