Amazon staff member Jinesh Varia has written a white paper in two parts that describes a "cloud architecture" application built on the SQS, EC2, S3 and SimpleDB services, and discusses best practices for using these services.
This paper is an excellent resource for anyone designing a scalable application based on AWS, especially Part 2 and the section "Tips for Designing a Cloud Architecture Application" in Part 1.
The paper is available as web pages here:
- Building GrepTheWeb in the Cloud, Part 1: Cloud Architectures
- Building GrepTheWeb in the Cloud, Part 2: Best Practices
There is also a PDF document version that includes a bonus extra: an appendix that summarizes the differences between the three data storage services -- S3, SQS, and SimpleDB -- and explains which service is most appropriate for particular tasks.