The Rapid Repair crew ventured to France to obtain an early iPhone 3GS, dismantle it, and scope out the inner components. Their discovery? The same 600 MHz CPU powering the Palm Pre (that can actually run at 833 MHz).
Though the two phones share the same CPU and GPU, they run on different chipsets (iPhone: Samsung SoC S5PC100, Pre: TI OMAP 3430). However, this Samsung chipset is also capable of handling 720p video recording, streaming vid conferencing and even Dolby 5.1 audio processing, giving this hardware some serious future potential.
AnandTech also posted an interesting theory regarding this particular chipset and battery life last week after the 3GS announce. They noticed that the CortexA8 processor can use up to 3x more power than the previous ARM 11 in the first two iPhones, yet battery life managed to improve with the 3GS. At the time, they thought the hardware might be using a process similar to Intel's Quick Start technology, which saves power by quickly ramping the processor up to full power when in use, and then dropping it down to an idle state when not in use actually averages out saves more power than running it at more constant power levels.
This might explain the improved battery life. Then again, the increased-capacity battery (1219 mAh, compared to the previous 1150 mAh), might also have something to do with it. [AnandTech and Rapid Repair via Engadget]