TUAW has a great post today about the likelihood of Apple switching its desktops & laptops to ARM from Intel:

Is ARM really a threat to Intel? Yes, absolutely, and especially as we transition into Apple’s Post-PC world. But there is next to no chance Apple will replace Intel chips for ARM-based ones any time in the next five years. In fact, there’s a good chance the exact opposite could be true, and Intel chips will be powering our iPhones and iPads by then. Here’s why.

There’s also an excellent elucidation of the differences between ARM’s architecture & Intel’s. Definitely an article worth reading.