I used already the S3 Storage from Amazon together with an Ruby on Rails App to store images. It worked pretty good for me. Now I am experimenting with EC2, the Elastic Cloud Computing. Here are some good links to start:
http://aws.amazon.com/ec2/faqs/
http://docs.amazonwebservices.com/AWSEC2/latest/UserGuide/index.html
Robert Reiz 