Again, I have a 2.4Ghz MB, not MBP but am experiencing a similar issue. Walked into a local apple store this evening and got some info I wanted to pass on. First, the 'genius' knew about the issue and was sympathetic to the problem. He presumed Apple corp was working on it but was careful to say he had not heard (or been authorized to say) anything specifically from them but to be sure to keep posting on the forums or writing letters to them. Second, he said they don't recommend boosting fan speed (damages CPU, he said); rather, to stop playing WoW or using other apps that crash the machine/increase the heat...
He also recommended installing Windows in bootcamp and trying it that way: different OS, different drivers, different software.
He seemed to hope for a firmware update, though I told him I was very disappointed if all that update did was gimp the GPU.
I see a new firmware update (1.3 for MB tonight), so will give that a try. Hard to say what fix will be, but as a fairly recent switcher this is very concerning.
I will write a snail mail letter to Apple corporate and others should maybe do the same.