After literally years of rumors, Google has launched its much-talked-about e-commerce payment system, Google Checkout. The idea is simple: Google holds on to your credit card and shipping information, and when you find something you want to buy at a Google Checkout affiliate, completing the transaction is a one-step process. "The goal here is to make it be one nanosecond from the time the customer decides to buy to the time the transaction is complete and the product is on the way," says Google CEO Eric Schmidt in the New York Times' coverage of the launch. Google has a trick up its sleeve for luring in merchants, too: If you're a merchant who buys advertising from Google AdSense AdWords, Google will waive some or all of your Checkout transaction fees. But for those who don't enroll in AdSense, the fees are still comparatively low: 20 cents per transaction plus two percent of the purchase price.