Choose File->New Project within Visual Studio and
navigate to the "LINQ Preview" node in the project-type
tree-explorer. Then select the "LINQ Library" project icon
and create a new LINQ enabled class library.
This will create a class library project whose
MSBuild project file enables compilation support for LINQ. A default
"Class1.cs" file is added to the project - I
recommend just deleting it to start with an empty project.