Was talking with the Apple engineers at WWDC which technical data sheets to look up concerning the GPU within the new iPhone. It's the PowerVR SGX 535.

This chip is one up from the Palm Pre which is the PowerVR SGX 530.

The difference between these is more video based than anything else. 535 has hardware acceleration for H.264 encode/decode, MPEG 4 and JPEG. It also handles HD content to 720p in real time.

These specs seem to give a hint to what Apple are planning for future upgrades of the iPhone or other device. Suggesting, that if your developing for the 3GS then you're already developing for the next generation too.