Originally, Microsoft seemed to be promoting LINQ to SQL in that place. However, since the introduction of .Net v3.5, Microsoft has folded on that, announcing that it won't be supporting LINQ to SQL for long, choosing to go with the Entity Framework instead.
The ADO.Net Entity Framework is an O/R mapping framework. Its main goal is the following:
An ideal environment for creation of business applications should allow developers to describe the business logic and state of the problem domain which they are modeling with minimum or no "noise" coming from the underlying representation and the infrastructure that supports it. Applications should be able to interact with the stores that maintain the persistent state of the system in the terms of the problem domain; specifically in the terms of a conceptual domain model, completely separated from the logical schema of the underlying store.
The EF architecture places emphasis on the model as being the core element of focus, facilitating a Model Driven Development approach to application development. Alternative approaches, such as Domain Driven Development, are supported by third-party frameworks, such as S#arp Architecture.
EF hasn't been well received by developers, probably due to the initial lack of support for several features. An interesting essay by Frans Bourma, discusses the shortcomings of EF.
Microsoft has taken such criticism to face value, and is investing heavily in the frameworks further development. An updated version of the Entity Framework will be shipped with .Net v4.0, and is expected to fix these shortcomings.
