Here's another good spot for people seeking knowledge - there's a fabulous bookstore attached, though nothing specifically musical.
I'm sure someone with more knowledge (and time!) could say this better, but having shared ritual with some of my friends who practice earth-centered spirituality, I can tell you that there is an emphasis on chant - type music. Often, voice and simple rhythm and words are used to focus and integrate body, mind and soul into worship in precisely the same way Gregorian chant, or other sacred musical traditions are used.
In women's spirituality circles, there is a growing body of beautiful hymns, which deserve to be more widely known.