LinqPad is already a cool tool for querying databases using the familiar LINQ Query Syntax. I talked about it awhile ago at LINQPad - Dynamically Query SQL Server Databases in LINQ.
A new feature in the beta version of LinqPad is the ability to query ADO.NET Data Services ( soon to be know as WCF Data Services ).
Per the website:
“LINQPad lets you interactively query SQL databases in a modern query language: LINQ. Kiss goodbye to SQL Management Studio!
LINQPad supports everything in C# 3.0 and Framework 3.5:
- LINQ to Objects
- LINQ to SQL
- Entity Framework
- LINQ to XML
- ADO.NET Data Services (in the latest beta)
- (Even old-fashioned SQL!)“

You can learn more about the latest beta version of LinqPad that supports ADO.NET Data Services here.
Check out other .NET Developer Tools.
Microsoft .NET Developer Tools