Streaming Video on Amazon EC2?

An Amazon EC2 Flash Video Streaming solution has been announced by Wowza Media. What do you think about the future of similar solutions? Is Amazon EC2 and S3 ready for video streaming?

I have found threads on their forums related to the performance, scalability and high availability of the hosted streaming solution. How would you make it scalable? Is it really cheaper than traditional hosting?

Looking forward to your thoughts!