The Vietnamese iPhone 4G which surfaced a few hours ago showed the interesting picture of the Apple A4 processor on a board; yep, the new iPhone 4G will have an Apple-branded processor although, just like all Apple products, someone else is manufacturing it.
The A4 is based on ARM's Cortex A8 architecture and according to Chipworks and the serial string - "339S0084" - we saw on the chip, is the same as in the iPad.
Ditto for the CPU die marking (APL0398) and one on the Samsung DRAM module (K4X2G643GE). The last string - YN6024Z3 - could be the batch number according to industry insiders, which comes handy when having to trace back errr leaks for example.
The A4 in the iPad is clocked at 1GHz and is likely to be underclocked in the iPhone 4G to increase battery life. That said, the Snapdragon SoC, which is also based on the Cortex A8 processor, is clocked at 1GHz and used in the wide range of smartphones like The HTC Desire and the X10.
However, we would bet that Apple has the upper hand after the acquisitions of Intrinsity and P.A. Semi against the rest of the competition
This latest revelation shows that the iPad is just a bigger iPhone without the phone bit; expect the next gen iPod Touch to come with the same processor.