There are a few posts on this site about OpenGL and the iPhone. Some even on books but I think you'll find this question is a bit different.
I've searched and searched and have come to the conclusion that there are currently no books that specifically cover OpenGL ES on the iPhone platform. There are books that cover OpenGL ES [2.0] (note: the linked book covers OpenGL ES 2.0 but the iPhone uses OpenGL ES 1.1 which, I understand, is not backward compatible)... but they only have a small section for the iPhone (if any).
What I want to know, is if anybody knows of any books that are forthcoming that specifically cover OpenGL ES 1.1 on the iPhone?