If you are registered with Apple's developer sites, I strongly recommend the OpenGL and OpenGL ES video talks from WWDC 2010. The Apple engineers spell out in a fair amount of detail things that you had to infer previously, including:
How state information is accumulated and then resynchronized at draw call time.
How resources are synchronized and shared between host memory and the GPU.
The videos are in QuickTime format with subtitles, so you can play them back at 2x speed with captioning to get through the material faster.