Starting today, online shoppers in the U.S. will begin finding a second checkout icon at some Internet retailers. You can now not only search for products using Google or its other products like Froogle, but you can use the new Checkout online payment service. Think of it as an alternative to the traditional—and still present—checkout process you find at online retailers, in which you fill out your pertinent personal information, shipping address, and credit card.

With Google Checkout you'll follow this traditional process just once when you register for the service. Then when you are headed to a partnering retail outlet's checkout process, you'll simply click the blue Google Checkout icon (see our slideshow) and all the other stuff will be taken care of for you. One of the big selling points the folks at Google are hyping is that if you already have a Google or Gmail account (or some other Google account), you can easily add Checkout to it and then make use of the service with a single login. There are other perks, too. For example, Google will reimburse you for fraudulent purchases; you can keep your e-mail address(es) invisible to merchants to prevent getting unsolicited e-mails from them; and you're able to view a purchase history that includes all your online purchases and the shipping status of your orders.

Google has agreements in place with all the major credit card companies, including American Express, Discover, MasterCard, and Visa, and also has a special promotion in the works with Citi customers.

While buy.com was the single largest online retailer mentioned during my interview with Google, a handful of other well-known brands were also disclosed, including Jockey, Starbucks, and Timberland. Google representatives hastened to add that there would be many more rolling out use of the service soon; in fact you should start immediately seeing Google Checkout logos on retailer advertisements that use Google's search advertising program AdWords.

That makes for a good segue into another component to all this that may be of less interest to consumers: online merchants that utilize AdWords will find they save a lot on the transaction processing if they in turn sign on as a Checkout partner. Specifically, Google will process $10 in sales free of charge for every dollar a merchant spends buying AdWords advertising. Google representatives explained that this represents an ongoing commitment as well.

The folks at Google have tried to make it easy to integrate Checkout into retail Web sites as well. There are cut-and-paste buy buttons, as well as an advanced API for building the service directly into existent merchant shopping carts and order-management systems.