unfortunately amazon.com and amazon.co.uk are independant, and the link wouldn't work for both.
That and I only signed up to the english associates, and i'm not sure amazon.com allows foreign signups to their affilate program.
I disabled it because no1 seems to buy anything off of amazon anymore. I put a paypal button in it's place
If it's movies your buying, get them from here:
http://www.play.com
Click region 1. Much cheaper, fast and free delivery too