Myth Village has reported that GameSpy has put up an article entitled Inside The Myth III Soundtrack. Zak Belica, composer and sound designer for Myth III, is interviewed in the feature. Belica discusses his background in music and what he aimed for with the soundtrack:

Since the game takes place 1000 years or so before the first Myth game, we wanted to make the music a tad more primitive and tribal. To achieve this, we went for a more spare sound, with a few more basic instruments per track instead of giant orchestras. The percussion used is also primitive; I used shield hits, metal strikes and leather/skin drums to give the parts a home-brewed feel. Scott Campbell and I went through the game and created an outline of the kinds of music needed for each section of the game. We came up with headings such as Journey, for when the player is traveling, Mourning for sad events, and Hero for when Connacht is in charge, etc. These headings are reflected in the piece names and in the music itself.

Each track's significance and philosophy is discussed briefly and it is clear that the soundtrack will definitely benefit Myth III's atmosphere.

In addition to this, the entire soundtrack is available to download for free. It's a 64.4 MB compressed ZIP file containing MP3s. I am downloading it right now and you should, too!