On PHPBuilder.com they've posted a tutorial showing you how to connect your PHP applications to Google Cloud Storage with the help of a Google App Engine instance and their own SDK.
In this article, I'll show you how to take advantage of Google's Platform as a Service (PaaS) in order to create a scalable, highly available and secure PHP web application. Note: The instructions are for Mac OSX, but may work for Linux too. Slight modifications may be needed for Windows.
They show you how to use the SDK and a bit of configuration to create a simple script that connects to the Google Cloud Storage (via a simple file_get_contents call), fetches a list of images and pulls out a random "meme" image to show from the list. They've also posted a live demo if you'd like to see the result.