Tutorials and libraries for OpenGL-ES games on Android

What tutorials and libraries are available which can help beginners to develop 2D and 3D games on Android using OpenGL-ES? I'm looking for tutorials which can help me learn OpenGL-ES, and I'm looking for OpenGL-ES libraries which can make life easier for beginners in OpenGL-ES.

iPhone board game: OpenGL ES or CoreGraphics?

I want to program a board game (similar to checkers) for the iPhone. Would OpenGL ES or CoreGraphics be a better option? What do most games of this type on the App Store use?

Any GUI libaray for iPhone & Android based on OpenGL ES?

Since both iPhone and Android support OpenGL ES, is there any open source or commercial GUI library we can use for these two platforms? Or is it doable (or how difficult) to port an application from one to another platform?

Learning OpenGL ES 1.x

What is the quickest way to come up to speed on OpenGL ES 1.x?

Is it possible to switch focus from one GLKview to another without reloading everything?

I am making an opengl 2.0 based game for iPad where I have added support for external displays. I want the game to be able to hot-swap between the local display and the external display.

iPhone opengl es: Touch detection

I have been messing around with opengl es on the iphone and right now I have some cubes on the screen. Currently I am trying to detect touches on these cubes. After a lot of searching on google this is what I have so far

Accurately Converting NSString to GLFloat - iPhone

Say I have some vertice values which I am reading into my app as a NSString :

Which part of OpenGL ES does make my iPhone App bit slow?

I am currently developing my iPhone App with OpenGL ES. It is mirror app with brightness and contrast. But the problem i am having now is it is bit slower(about 0.2s delay) when you use it. But the frame rate is about 60 seconds. So my quesion is which part of OpenGL takes time to process?

Is there any alternative for GLES20.glClear(GLES20.GL_COLOR_BUFFER_BIT)?

I get a fill rate of about 30fps in my application. I know that GLES20.glClear() is used to clear the screen for every draw. If i comment it i get a fps of about 60fps. But the output is not as expected. I have a content to be redrawn for the whole screen in every frame. Is there any alternative where i can redraw the whole screen with out using the GLES20.glClear(). Please let me know if there is any way to play around with GLES20.glClear() to improve the performance?