If you've bought iPhone 4S, you probably know by now that Siri is integrated with Wolfram Alpha - the computational knowledge engine. You can force Siri to use Wolfram by prefixing your request with "Wolfram."
But the problem is, it doesn't tell you what all you can do with Siri. iPhone expert and developer, Erica Sadun along with Steve Sande has released an ebook called "Talking to Siri" on the Kindle store, which teaches you how to use Siri from ground up.
