To be more precise, Amazon Flexible Payments Service (http://aws.amazon.com/fps/)

Thanks, their website is a bit hard to navigate, they only emphasized simple payments and Amazon checkout.

I can't seem to find if it's only available to US/UK users, or if it can be used for clients world wide. We're based in the US and are currently using Google Checkout (which works great), but would like to offer our users an alternative.

It says somewhere they can be used by customers in many countries, but the vendor can only be in the US, I think.

Ah, good catch, why didn't I think of that? Are they available for UK banks? I'll look now, thanks...

No they're not. You need a credit card from a US bank. Amazon FPS has some really good aggregate payment features that I can't find anywhere else, so I'm starting a US company primarily to get round this.

Ah, that's why I didn't think of them :( That is terribly unfortunate. They seem to be the best option so far, and if the only alternative is Braintree, it seems that the project is dead before it even begins...