Microsoft has a bunch of samples on their sitethat show how Lambda Expressions, LINQ, DLINQ And XLINQ work in Visual Studio Orcas Beta 1
This is what is available right now
C# LINQ Samples and content for Beta 1
C# LINQ Samples and content for March CTP
VB LINQ Samples for Beta 1
If you install C# LINQ Samples and content for Beta 1 then you will see the following examples
Data
DynamicQuery
ExpressionTreeVisualizer
LinqToNorthwind
ObjectDumper
PasteXmlAsXLinq
Reflector
Rss
SampleQueries
SimpleLambdas
WinFormsDataBinding
XLinqIntro
XQuery
In addidion to the samples there are also these five whitepapers in the whitepapers folder.
LINQ to SQL Overview for CSharp Developers.doc
XLinq_Overview - Feb.doc
LINQ Project Overview.doc
CSharp 3.0 Specification.doc
Standard Query Operators.doc
This is all a must read if you want to get started with .NET 3.5
Here is the download link in case the URLs above changes: http://msdn2.microsoft.com/en-us/bb330936.aspx