An interesting article from the European Review of Native American Studies (2005). From the opening paragraph:

One need not accept Harjo's unfounded claim that the word redskin "had its origins in the practice of presenting bloody red skins and scalps as proof of Indian kill for bounty payments" to accept that many find the word objectionable in current use. But the actual origin of the word is entirely benign and reflects more positive aspects of relations between Indians and whites. It emerged at a specific time in history among a small group of men linked by joint activities that provided the context that brought it forth. Before its documented history can be traced, however, the false history given for it in standard reference books must be expunged.

Thanks to Bill Poser (Language Log) for the pointer; he has more on the subject, including on the specific history of the term as the name for the team. I stress again that one's views of whether the Washington Redskins should keep or change their name need not be dictated by this history; but it struck me as interesting history nonetheless, especially given that the critics of the term have relied in some measure on their own accounts of the history as well.