One of the things that has folks most excited for the iPad's release is the A4 CPU which, it has been noted, is freaking fast. As it turns out though, calling it a CPU is rather inaccurate. The Bright Side of News has an in-depth report on the A4, in which they reveal its true origins.
The A4 is what is called a "System on a chip" or SOC. It consists of a main processor, in this case an ARM Cortex A9 multi-processing core (based on the same ARMv7 architecture found in Tegra and the Snapdragon) and a graphics processing unit, in this case the ARM Mali 50-series. The A4 chip, designed by Apple and PA Semi-conductor, is primarily based on ARM IP.
So there you go. Apple's fancy new chip isn't all-Apple, and it is very similar in design to the chips Nvidia and Qualcomm are putting out for other tablets and smartphones. This means that other tablet manufacturers will have some very similar hardware options to choose from when they design their iPad-killers.