Lessons:
NeHe Productions: Main Page
OpenGL ES reference:
OpenGL ES 1.1 Reference Pages
One key thing to remember is that in plain OpenGL you can draw single vertices etc one at a time. In the embedded (ES) version you put all the vertices in one big array and hand the array to the hardware. It's no harder, but you will see single vertex operations in a lot of tutorials.
My advice when approaching OpenGL is to remember that you're dealing with a special piece of hardware. You tell it what you know about the world (triangle points, lighting options, textures, etc) and it renders it for you. Also the drawing of a scene as a whole is really complex, but each little piece is not. You can do it.
