The OpenGL ES Emulator allows you to emulate OpenGL ES code on your PC. It's actually very cool. You just need a fairly recent AMD video card on your machine.
The emulator is available at:
Current version is 1.4 (April '09)
Like all products however, there are bugs in this code. Lacking any other place to put them, I'm going to create a new thread for posting them. Hopefully someone at AMD will address them in the near future.