Google Store uses Oscommerce (popular open source PHP ecommece store management program) and free open source plugins are available to integrate google checkout with oscommece in minutes (eg: http://code.google.com/p/google-checkout-oscommerce/). I wonder why they cant simply use Google checkout to deal with credit cards on their own site?

Screenshots
1) Google store without Google checkout option for payment.
2) Worldpay message when checkout starts.

Another question
OK, now we know that Google store doesnt have Google Checkout support at the moment. Then how does the store have the google checkout badge on their sponsored listing?

Google search result shows the Google Checkout badge

Try a Google search for “Google Store” and you can see the sponsored link has Google checkout badge on it.

NOTE: I love Google and use most of their products. Just don’t understand why they cant use their own checkout in their official store.