basically "berdache" is a word for people among some native american tribes who took on the roles of the opposite gender. they were highly respected members of their society. some queer thinkers yank berdache out of its historical and cultural context, equating it with being "gay." berdache were respected and revered until Western culture arrived in the "new world."
Here's a good site about berdache with good links by Berdache Jordan
why the word 'Berdache' is colonialist.
For your intellectual jollies here's an essay I wrote on the berdache as a senior in college. Nine years later it definitely needs a rewrite or two.