The amazing iPhone 4S is out and one of it's best features is Siri Personal Assistant, ask Siri a question - using natural language - and Siri will find the answer. Want to check the weather in London? just ask Siri. Call a taxi in San Francisco? no problem. This is the best app for the iPhone 4S, and a compelling upgrade for iPhone 4 owners.
Siri Personal Assistant uses the iPhone 4S's apps to send emails, set reminders, find directions, use Siri to check the weather, and you can even set an alarm to wake you up. Here is a live demo of Siri in action: