Today Amazon announced a new feature, “EBS Shared Snapshots”:
Amazon EBS shared snapshots make it easy for you to share this data with your co-workers or others in the AWS community. With this feature, users that you have authorized can quickly use your Amazon EBS shared snapshots as the basis for creating their own Amazon EBS volumes. If you choose, you can also make your data available publicly to all AWS users. Because all the data is stored in the AWS cloud, users don’t have to wait for time consuming downloads, and can access it within minutes. You can quickly start sharing your data through the AWS Management Console by visiting the Snapshots section in the Amazon EC2 tab, or by leveraging the API Tools.