ADO.NET vNext CTP
If you have not already heard, then there is a new CTP of ADO called ADO.NET vNext which adds support for both consuming and creating EDM (or Enterprise Data Modeling which some people know as Data Modeling or more commonly known as Entity-Relationship Models). If you want to get a quick overview of what this provides, then check out the 13 min demo (via flash) on what it does. There is also support for LINQ (or Language INtegrated Query). There aren't any visual designers in this drop, but expect those to be added in the future ones. You can download this from here and get more information on the ADO.NET team's blog.