You take your iPhone 4S out of your pocket and ask Siri to schedule an appointment. It's a great convenience, yet it still entails getting our your iPhone. But suppose you could ask Siri to do that task by simply speaking to the iPod bracelet you're wearing, or to the iOS device in your sunglasses? As always, Apple is marching ahead with its vision of personal computing. On Sunday the New York Times reported that Apple is developing wearable computers.