“This site (http://shop.uppercasegallery.ca/) has a shopping cart the likes of which I’ve never seen before. It’s pretty slick; it slides in and persists at the bottom of the screen, unless the user closes it. With my limited knowledge of the newer technologies of the web, I’m assuming it employs JavaScript and maybe a little bit of Ajax.”

It is indeed a nice shopping cart application, but it actually uses a 3rd party provider called Shopify made by Jaded Pixel. While I don’t want to do a product review or endorsement you can set Shopify to work on your domain and even have control of the interface. They’ve even released their templating language called Liquify as open source for Ruby on Rails applications (similar to Smarty on PHP).

You have options to leverage JavaScript frameworks to build something similar such as the shop module in script.aculo.us. Many JavaScript frameworks offer a combination of drag-n-drop/Ajax that can be used to build similar functionality. Unfortunately, code samples are impractical in this example, because it varies on what framework utilized and programming language.