I'm afraid I'm going to be a bt vague here, but GL over X seemed to be working on the original raspbian pisces_r3 image (the one before the official release).
At least I was able to run 'critterdings' on the pi, with the ouput on my mac at 24-30fps (2fps when running only on pi). Is that what you were after?
I've tried the same thing on the official raspbian image but nothing gets output. I had a quick look but couldn't find anything obvious and then I run out of time (I'm running code on the squeeze image atm)
Sorry for the vagueness, but hopefully it'll point you in the right direction. As to whether it's useful as per above GLES post I don't know.