This is a simple API to access Amazon SQS, EC2, SimpleDB, FPS and DevPayLS web services. It uses the QUERY interfaces. This code is thread-safe and works very reliably to the best of my knowledge. I've been using it on a system where sending messages in SQS is critical and we manage pools of servers on EC2.
This library is kept up to date with the most recent API changes and user feature requests. See the project page for more details. http://code.google.com/p/typica/
A tool for SimpleDB is also available. It's called sdbShell and supports all of the commands that the API supports and is especially useful for testing queries.If you like to play with queries in SimpleDB, another associated tool is QueryTool, based on typica. http://coderslike.us/2009/09/18/querytool-now-exports-data/