Apple is finally going to make its own ARM chips for Macs
About time, although I don't think they'll switch to them in Macs until they have an ARMv8 64 bit chip ready, which should be in 2014, along with everyone else. Expect amazing battery life for future Macs, that should also be cheaper, and will also have much better performance than today's iPads because there's still 2 generations of ARM chips to come out until then, and that's even if they don't decide to make a higher performance chip with slightly higher power consumption (think of it as a beefed up version of the Apple A7 or A8 chip).
Apple's moves towards making their own chips is clearly indicating they want full control over their own chips, so this will definitely happen, although it doesn't necessarily mean they will get rid of all Intel chips from their whole notebook line-up. But they will probably introduce some new type of even thinner and lighter Macbook Air (and cheaper, too).