This is just another shitty way for Amazon to pay affiliates even less commission than they already do. It's *all* Amazon, so why not just let affs create one account and it works for everywhere..?!
Based on my main site's primary traffic, I didn't bother getting an account for anywhere other than the US and Canada, but will probably register for the UK as well.
I also use to redirect my outbound aff links through geotargeting (Cnd clickers to amazon.ca, USA clickers to amazon.com) - and am sure that it was working in the beginning, but seems to have broken now...
So if anyone knows of an easy to use and solid, cheap (or free) geo script like that, post it here. thanks.