There are several different Plugins that will help you add Amazon.com ads, wishlists, current reading lists, and other Amazon ad types to your WordPress blog.
The Plugin that does it all is known as Amazon Media Manager WordPress Plugin. The Amazon Media Manager allows you to select Amazon.com books, music, and products from within your WordPress Administration Panels and easily add them to your WordPress blog in a plenty of different ways.
WP-Amazon WordPress Plugin lets you to search Amazon as you write your post and embed the Amazon information directly into your blog post or Page. This is pretty contextual and has more chances of doing well.
Last Amazon Review WordPress Plugin depicts your most recent review on Amazon.com, helping you to promote any book or a product.
Amazon Wishlist WordPress Plugin lets you put your Amazon.com wishlist embedded on your WordPress blog.