It's been pouring with rain here all day, so I seized the opportunity to knock out a quick release of Ruby/AWS.
Version 0.4.0 allows the user to retrieve existing shopping-carts from AWS using the new Amazon::AWS::ShoppingCart::Cart#cart_get method. I hadn't originally implemented this method, because I considered it unnecessary in view of the fact that shopping-cart state was already maintained in Cart objects. Should these objects cease to exist, however, there was no way to resurrect the object from AWS's servers. That has now been remedied.
This version also requests the newest version of the Amazon AWS API, namely 2008-06-26 and fixes a bug in the Amazon::AWS::ShoppingCart::Cart#cart_modify method.
As of this release of the software, I consider Ruby/AWS to be in beta. In other words, you may now consider it fit for non-critical use. It had been that way since version 0.3.0, really, but I was being cautious.
If you're a user of the remote shopping-cart functionality, you should upgrade.