We all know that multitasking is an important part of iPhone OS 4, mostly because we’ve been told its important. Multitasking, or the ability to run multiple applications at the same time, is not an easy feat of engineering, but Daring Fireball’s John Gruber breaks it down and makes it easy to understand. If you’ve wondered what all the hubbub is about, this is a must read.

Mobile Multitasking [Daring Fireball]