According to Bright Side of the News, it turns out that newly spun Apple A4 system-on-a-chip that debuted alongside the iPad does indeed pack more punch than the Sammy in the iPhone 3GS:

A4 is a System-on-a-Chip, or SOC, that integrates the main processor [ARM Cortex-A9 MPCore i.e. Multi-Processing Core, identical to ones used in nVidia Tegra and Qualcomm Snapdragon] with graphics silicon [ARM Mali 50-Series GPU], and other functions like the memory controller on one piece of silicon - not unlike what Intel is trying to achieve with its future "Moorestown" Atom processor that debuted inside LG's Smartphone

Cortex A9 indeed? But no PowerVR SGX like the iPhone. Engadget says this is also similar to the Tegra2 platform. So, it's more of an Apple assemblage of ARM components rather than anything PA Semi unique, but is it a first step towards more customized silicon? Either way, we'd still love to see this baby powering the 4th gen iPhone and iPod touch.

Still no word on RAM though...