Amazon checkout USA?

I have started to receive amazon solicitations to start using amazon checkout. I am USA based so I am guessing I should be able to accept payments through amazon in the USA.
Looking at the Amazon payment module in 1.5.6.4 and it has UK and Germany. So maybe not ready for USA. BUT the play side to myself says maybe change the URL to the amazon URL and the currency code to US and it might work?

Or is there another topic that already has a solution that I missed?

Thank you,

Mike

Same thing happened.
I received e-mail many times to recommend Amazon Payment from Amazon (I believe) which tells now Amazon and Open cart is connected and if I register it, Amazon will contact Open cart something like that (affiliate program???).

Anyway, since I'm interested in Amazon express payment, I'd like to register but before that I've read how to integrate with my site on the Amazon site, it seems too difficult for me.
I use Opencart 1.5.4.1 (I like it) and since I have no extension on my admin. control panel, I really don't know how much effort I have to spend to integrate.

If somebody tried, please let me know. Anyway, if express, I have to set up the Shipping & Tax things on the Amazon site but if you want is as just one of the Payment methods, it looks like PayPal Standard.