The new OpenSocial client libraries utilize the OpenSocial REST and RPC protocols, and they are available in four flavors. Pick your choice of Java, PHP, Python, or Ruby, and you will be on your way to developing some social applications.
According to the OpenSocial Blog:
Each library enables developers to retrieve profile information and persistent data from supporting containers without having to concern themselves with managing network connections, signing requests, or other lower-level details.
These containers are a great addition to the other resources currently available for OpenSocial. Be sure to check out our OpenSocial API profile as well as the OpenSocial Developer web site for additional information.