I've been experimenting with Amazon's new CloudFront CDN service since the launch and thus far it's proven to be a good option provided you don't need to update content in anywhere near real-time (you are pretty much looking at 24 hours before content updates hit the full network.)
And while the functionality doesn't match something like Akamai, my best math effort suggests that the service will cost you 10% (or less) than Akamai does for static image serving, which makes the service very compelling.
Paul Stamatiou wrote up a great how-to guide for CloudFront and it shows how setting up the new service is still not for the faint of heart. You still need to be a developer/admin type in order to get everything up and running.
The net result:
I'm pretty happy with Amazon's first CDN offering, CloudFront. It's extremely easy to setup and affordable to boot. I was able to get it running from scratch in under 5 minutes, including CNAME DNS propagation. While it might not be mature enough yet with advanced usage reporting for companies to use in place of Akamai, Limelight or CacheFly, it certainly has potential.
Where CloudFront will start to get really interesting is when it can do real-time video at this low cost. Until then it's a nice option to speed delivery but still not a full-blown commercial CDN.