How do I sign up for S3/CloudFront account?

It is really simple to sign up. The only thing you need is an email address and a valid credit card. You won't be charged any money upfront, you pay as you go along. The pricing is very low. Go here http://aws.amazon.com/s3/ to sign up and click on the Create Free Account link. From there, follow the instructions.
We had a tutorial for this with screenshots but the interface of AWS changes so frequently that we could not keep up with it.

Updated: July 27, 2013