Beagle - 11:44 pm on Aug 7, 2007 (gmt 0) [edited by: Beagle at 11:46 pm (utc) on Aug. 7, 2007]
The page jwolthuis gave the URL for is set up for buyers to register - not sellers. To use the payment process from a merchant's end, read the info and follow the links in the "Are You a Developer?" box on the same page. Or just go to the Web Services part of the amazon site.
[edited by: Beagle at 11:46 pm (utc) on Aug. 7, 2007]