I've developed a new plugin for WordPress. Its called AZ-One and it is developed for Amazon associates. The plugin helps associates to create more income by showing Amazon associate links based on the visitor's country.
The basic problem is that if the visitor clicks the associate link in the post, likes the product but orders it from another Amazon site, the associate won't get the referral fee. So it is beneficial to direct the visitor to the Amazon site that he would most likely buy from.
If you have for example created a link to Amazon.com in your post and you have a visitor from Europe, the plugin will change the Amazon.com link to Amazon.co.uk or some other European site (de, fr). The plugin supports directing visitor's to Amazon com, ca, fr, de, co.uk and jp. There are 234 countries in the plugin's database and the blogger can choose which Amazon store is shown to a visitor from each of those countries.
The usage of the plugin is really quite simple. It converts the existing associate links in the posts, so there's no maintenance needed for existing posts.
The plugin is available for free from my blog: http://www.52lives.com/downloads
Hope you enjoy it!