Native American religion, mythology and folklore are covered extensively at this site:

A long-standing problem with this section (and several others at this site relating to traditional peoples' spiritual beliefs) has been the lack of authoritative information. We are in the process of expanding this section by scanning public domain ethnographic accounts on specific Native American religious and spiritual practices. We are fortunate that there is a wealth of such material available, which makes it so much more puzzling why more of it is not on the Internet yet.

The study of Native Americans by anthroplogists has had its share of bad science and ethical problems. However, the texts we are in the process of scanning were written by 19th and 20th Century ethnographers who were known for their careful and respectful approach to the people they studied. These were scholars who lived for years with the people they studied, and obtained permission to transcribe their oral sacred literature.