Is there a comprehensive tutorial related to the development of custom payment extension for magento 1.7. I found these article but they are old and I have the same code already in amazon checkout extension. http://inchoo.net/ecommerce/magento/programmatically-create-order-in-magento/
I started modifying an amazon checkout payment module which we are using in the old version of Magento. Now we have upagraded from 1.4 to 1.7 and the amazon module is not working. I have modified the code as in the googlecheckout module. Specially I modified the order saving and the order confirming functions. The module is now working but have a lot of issues, because many things are different that the googlecheckout module and also there callback response is different.
Also I have searched the amazon checkout extension for 1.7 but the one I found is not for US. http://www.magentocommerce.com/magento-connect/amazon-checkout-extension-9731.html.