WP-Amazon version 2.0 Beta 1.1 by Rich Manalang
Modified to work in WordPress 2.2 by Jacob Lundberg

Install Rich's WP-Amazon version 2.0 Beta 1.1, then...
Copy or upload the contents of this folder into your wp-content/plugins/wp-amazon/
(Some files will be overwritten / replaced.)
That's probably all you need to do.