Apple is very likely introducing a new CPU in the iPhone 5. It will also likely be called A6 and I expect it to be a quad-core. Now a supply chain rumor seems to confirm this.
The iPhone 5 is expected to be released this fall. It is supposed to be a major redesign and of course will be more powerful. Apple is expected to introduce the A6 CPU in the iPhone 5. Digitimes reports that the Apple A6 CPU is going to be built on the Samsung Exynos 4 quad-core processor. Quad-core CPUs are already used in several new smartphones. It is save to assume that Apple is going to bring also a quad-core CPU with the iPhone 5.