I'm currently working on an implementation of OpenGL that will be targeted towards the OpenGL ES specification. The project is called TinyGL. The original author released the source code to the public in March2002. I've set up a webpage at sourceforge:
It already provides a good subset of the OpenGL and GLUT APIs. This version is for the intent platform, but the code is extremely portable.
If anyone would like to help out in this project, please let me know. I think TinyGL is uniquely positioned to become a standard OpenGL ES implementation.