Amazon has this nifty feature called wishlists that you use to quickly mark things that you would like to have but aren't willing to buy yourself - well at least not on that day. Wishlists are kind of like wedding registries but without a real event to excuse you making such a list of greed. However, for families such as ours where everyone is so spread out I think the wishlist is a great idea. So, with that in mind I have added wishlist functionality to the site. Basically, what I do is use the amazon webservices (4.0) to pull down our wishlists to this server so you don't have to visit amazon unless you actually want to buy us something - nifty eh?
I saw a couple wordpress amazon wishlist plugins but nothing really did what I wanted and they all used an old version of the amazon webservices platform. So, I created a php class and a fairly simple function to interface with the class and BAM! we now have our wishlists integrated into the site.
Here is the php class file I use to create the wishlist display - it will also display a bunch of results from a search as well - but that functionality isn't really done yet.
And here is the function I call to display a wishlist. There are a few parameters you can pass in and in general I think they are pretty self explainitory - as always if you want to use this and have questions - just post them here as comments and I'll try to help you out.