More about Ixies » Amazon Commission
Ixion is an associate of amazon.co.uk, which means that the group gets commission from stuff bought through these pages - at no extra cost to you.
Find the amazonian thing you want, and then mosey on up to your browser's address bar.
You'll find it goes a little something like this:
http://www.amazon.co.uk/exec/obidos/ASIN/0340769211/
(There'll be some cruft to the right of that, but this is the important bit)
All you need to do is replace the cruft with the magic associate tag ixion-21, so it reads:
http://www.amazon.co.uk/exec/obidos/ASIN/0340769211/ixion-21
And you're done.
(Actually if you make it look exactly like that you'll have a (very good) book about WWII, so the product number will probly be different for you)
For our colonial cousins buying through amazon.com, it's the same procedure as above, but the associate id is ixion-20