In order to use you need:
I am on codenamed projects wave today and I would like to share with you another one - project Astoria (reposted from official blog):
Project Astoria Overview
The goal of the Astoria project is to enable applications to expose data as a data service that can be consumed by web clients within corporate networks and across the internet. Such data services are reachable over regular HTTP requests using standard HTTP verbs such as GET, POST, PUT and DELETE to represent the operations against the service. The payload format for the data exchanged with the service can be controlled by the client and all options are simple, open formats such as plan XML and JSON. The use of web-friendly technologies make it ideal as a data back-end for AJAX-style applications, Rich Interactive Applications and other applications that need to operate against data that is across the web.
Further reading: Astoria Overview, Using Astoria
By Mike Flasko
For those who are interested in architecture & design & process the team made another post