Libzcloud
libzcloud is a free and open source library for storing and retrieving data on cloud service (e.g. Amazon S3). It abstracts the details of the various services for applications. It uses plugins, making it easy to add support for new services; you won't need to rebuild the library or worry about licensing as much.
Contributions are welcome! Development uses the Git version control system. We recommend creating a GitHub account to share your changes. Click fork to make your own copy of the repository.