I’ve just checked in OpenGL ES 2.x support to CVS, including GLSL support of course.
It’s highly experimental, but functional (I can apply shaders to objects). Since the fixed-function pipeline is no longer there, we do need a shader generator with GLSL support though.
I don’t own an iPhone, but it seems to work on my PowerVR SGX 530 card of my OMAP 3530-based SoC. =) The iPhone 3GS uses the SGX 520, I believe, which is almost the same thing, but just 2x as slow.