I came across this article The Film Twilight and the Quileute Legend. In it talks about the Quileute Tribe and their true legends and ones that Stephanie Meyer made up.
After reading the article I decided to try and find out more about the Quileute Tribe and their history and to see if they really did have stories where they were descended form wolves. I checked out the Quileute Nation website
and read that indeed the tribe did have a story about transforming into wolves. According to their ancient creation story, the Quileutes were changed from wolves by a wandering Transformer.
I got sucked right into the site reading about their history and the different aspects of tribal life. They have a great file you can download called Raven Tales, click on the Stories and Legends tab under culture. You can hear some samples of the language in MP3 format. It really is a cool site and almost two hours after finding it I am still reading more about them.