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 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.