Yeah I'm with webdev, I'm a little confused as to how the amazon thing works and what would be the benefits of adding it to your site? What will it allow you to do? I briefly read about it on Amazon but I'm still not sure what you need to do to make it work and what are the benefits.
As far as a search box, a lot of SBIers use a Google search box on their site. I believe it's just copying and pasting code. Your visitors can choose to search your site or Google's. See the link below...
http://www.google.com/services/search.html