HDMI Audio + Video can be enabled on Mac OS X for most graphics card and motherboard configurations without much hassle using the replacement audio driver VoodooHDA. Using the supplied AppleHDA.kext for HDMI audio is something of a challenge, but provides numerous benefits including native Mac OS X support, high quality digital surround audio and overall system integration.
Over the past few months, toleda has been exploring and experimenting using different methods, and has come up with what we think is a pretty definitive series of guides on the subject. Please note that this is an advanced process and is highly dependent on your exact hardware configuration.
Enabling HDMI audio via AppleHDA in Mac OS X 10.6.x is comprised of four guides:
We've set up a new HDMI Audio subforum to host toleda's guides and general troubleshooting topics. Good luck!