Following the release of Visual Studio 2008, a handful of significant enhancements began to take shape, targeted for the SP1 timeframe. I'm sure most of you heard about the MVC Framework for ASP.Net, and you may have heard about the Dynamic Data Website, too. But I'm still surprised how many people haven't heard of Astoria (now called ADO.Net Data Services).
Built on top of the Entity Data Model, Astoria is intended to expose your entities as REST or JSON objects with very little extra work from you. Best of all, the Astoria controller understands the verbs needed to interact with this model in a standard way. Much like the Dynamic Data Website, once you set up the data model, you can have your web service front-end working remarkably quickly.