Amazon S3: New pricing model
blogs.smugmug.com
blogs.smugmug.com
"P.S. Please note that the reduced bandwidth rates shown above will also take effect for Amazon EC2 and Amazon SQS. The bandwidth tier in which you will be charged each month will be calculated based on your use of each of these services separately, and could therefore vary across services."
I've seen dedicated hosts that price bandwidth above their included allotment at $500 per TB. You can also buy based on peak bandwidth.
You'll see quite a range depending on business models, peak transfer caps, etc. Mediatemple, for example, is clearly hoping that most people will never need their full allotment, and when they do, they only need it occasionally.