The Google Checkout blog announced that they are now supporting Google Checkout for mobile devices. So if you are on the road, see something on your favorite site, that you must have, you can buy it using Google Checkout on your mobile device.
So if you are a merchant, you will need to enable your site to be WAP enabled and then integrated Google Checkout mobile.
GoogleCheckoutPro at Google Groups said:
US and UK Checkout merchants who have mobile-friendly sites can now offer their customers a fast and secure way to shop online while on the go. Existing Google Checkout buyers are now able to make fast, secure purchases on their mobile phones from any WAP-enabled Checkout merchant. The user experience has been adapted for mobile - for example, buyers can verify their identity using a PIN rather than a full password. Checkout for Mobile is currently limited to the sale of physical goods.
Old merchants need to upgrade - free of course. New merchants will automatically be supported.
Are you a mobile buyer and have questions, check out Google Checkout for Mobile help.
Forum discussion at Google Groups.