iPhone 4S picks up where amazing left off. It's the fastest, most powerful iPhone ever. It features an 8-megapixel camera with all-new optics. It records stunning 1080p HD video. It comes with iOS 5 and iCloud. And it's the only phone with Siri - your intelligent assistant that helps you get things done, just by using your voice. Now you can use your voice to use your iPhone. Just talk to Siri as you would to a person: "Do I need an umbrella? " or "Any great burgers around here? " or "Where's the closest ATM? " Siri not only understands what you say, it knows what you mean. It figures out the right apps to use to find the right answer. Then, just like a personal assistant, it answers you. Siri makes phone calls, sends…