Jeremy Likness blogged about the Entity Framework 4.1 code-first, Silverlight, SQL, and shared models using REST and JSON.
Source: C#er : IMage
It's a debate that has existed for decades. The database architects insist that data is golden and the most efficient way to build software is to generate it from the database schema, while the object-oriented code junkies swear that a nice "domain model" is the way to go and that persistence is a side effect of making those objects stick around longer. Of course, if you've worked on enterprise projects long enough you'll find the answer is often somewhere in the middle: some projects benefit from a database-centric approach, others from a model-centric approach, but many require a outward in approach. Design the schemas for the database to do what it does best with relationships, design the domain model to encapsulate the data and behavior of the class, and translate one to the other (hence the ORM, or object-relational mapper).