I just ordered it 2 days ago directly from O'Reilly website (they currently have "buy 2 get 1 free" promotion, just use code OPC10, http://shop.oreilly.com/product/0636920025108.do). Really excited to read it when it comes. In case you're curious the other 2 books I ordered were "Python for Data Analysis" and "JavaScript Web Applications" which also look very promising.

Edit: Sorry, not a referral link.