If I remember correctly there are some of you that are interested in native american languages, here at Lingq. This site might be useful, it seems to be run by some sort of “semi-official” organisation so it seems legit.
They seem to have basic information on the language as well as language resources (links to other websites). The languages that they have resources for are Apache, Beaver, Carrier, Cayuga, Chipewyan, Cree, Mohawk, Navajo, Oneida, Onondaga and Seneca.
Edit: When I looked around a bit more it turns out that there is actually a “seemingly” full list of all native american languages with links to resources.
American Indian Tribal List: Native American Tribes and Languages