Many books written for children about Native Americans perpetuate stereotypes and disrespect. Debbie Reese reviewed Richard Peck's, "A Season of Gifts" in her blog American Indians In Children's Literature. In her post she quotes some passages from Peck's book and explains why it is disrespectful to Native Americans. An example is the disrespect shown to the dead in this story.
One of the headings in Ms Reese's blog is "Evaluate from an Informed Perspective". I love that title because it says so much. One site that she refers people to is Elaine Cubbins website and her recommendations for evaluating a Native website.
Another great source for evaluation advice is Oyate. They sell the booklet