There's a great article on Gamasutra on game audio, written by Andrew Boyd. He talks about: * the relationship between movie audio and game audio. * how games, both in terms of audio and generally speaking, are influencing movies. * some of the special challenges of game audio, with a concrete example of how those challenges can be overcome. * how the overall sound quality for the game Lord of the Rings: The Two Towers was achieved.
Finally, it contains some links to other articles on audio in general and the audio in Lord of the Rings: The Two Towers in particular.