Microsoft is working on a project called Astoria. It consists partly of a new technology acompanied with a library and partly of a free service. It's a data service that is reachable over regular HTTP requests and standard HTTP verbs such as GET, POST, PUT and DELETE. The data is formatted as plain XML, JSON or RDF (experimental). The service that is acompanied is a hosting service for this data service. You will get a 100 MB data service hosting for free. The Astoria runtime library makes use of the ADO.NET Entity Framework part of Visual Studio 2008 and .NET 3.5 and is built on top of Windows Communication Foundation. I'm very interested in this new technology. I might try it sometime in the future. But we have to remember this service is experimental. It might even cease to exist some day.

• Project Astoria Team Blog
• Astoria Online Service
• Astoria Online Service - Getting Started
• Sample Northwind Astoria Service - Customers in London Query
• Astoria Documentation