Amazon announced the Amazon Mobile Payments Service (Amazon MPS). Amazon Mobile Payments is providing developers, merchants and distributors of mobile applications an easy way to process payments from mobile devices and extend Amazon’s 1-Click checkout experience to their customers.
Amazon MPS enables tens of millions of Amazon customers to use the existing payment and shipping information in their Amazon.com accounts to make purchases from their mobile devices.
Amazon is still for many the easiest way to buy stuff online. Especially if you have 1-Click enabled, it is actually too easy as I just buy too much stuff on Amazon - I admit, I am lazy. Getting the ability to use Amazon to buy stuff from other vendors online on my phone is great for Amazon and great for the vendors.

More details about the Amazon MPS
Amazon Mobile Payments Service provides developers and merchants with a payment option for their customers that is as easy and familiar as the checkout experience on Amazon.com - including the convenience of Amazon’s 1-Click checkout. After signing in from an Amazon MPS enabled device or mobile application, customers are automatically able to make future purchases from their mobile devices using 1-Click functionality.
Through a simple set of API’s and an optimized mobile browser experience, developers and merchants can easily extend single or multi-use payment options to their customers. Developers and merchants who already offer Amazon Payments on their website can easily add the new mobile payment option for their customers without any additional backend technology development. More details on the Amazon MPS site.