In a new blog post Maarten Balliauw has mentioned a new release in cooperation of Zend and several major cloud services providers of a simple API that makes it easy to interface with Cloud Application Services.
The Simple Cloud API project empowers developers to use one interface to interact with the cloud services offered by different vendors. These vendors are all contributing to this open source project, making sure the Simple Cloud API "fits like a glove" on top of their service.
The API lets you work with things like Windows Azure blobs, Amazon S3, Amazon's SimpleDB and Rackspace Cloud Files. Maarten includes a bit of sample code using the new Zend_Cloud components of the Zend Framework to make a connection to Windows Azure and store/retrieve an item to and from the service. You can find out more about the interface and what all it supports on the Simple Cloud website.