If you work with LINQ to SQL then you might want to take a look at this posts of Dinesh Kulkarni:

 Also you may wanna check this free lab MSDN Virtual Lab: Mapping Your Objects to Database Tables with LINQ to SQL.


Event Overview

This lab shows how to access relational data using LINQ to SQL.  You will start by creating an object model for the Northwind database, and then use the object model to access the database using the new C# 3.0 query expressions and LINQ to SQL APIs.

You will next create an object model from an existing database using the LINQ to SQL Designer.  This part covers mapping relationships across tables and using Create, Update, and Delete operations. Use of the object model covers the use of transactions, object loading options, stored procedure integration and object identity with LINQ to SQL.


Finally you can download the DAT 200 Technet Session - New Thinking in Data with LINQ and Visual Studio 2008 from here.


DAT-200: New Thinking in Data with LINQ and Visual Studio 2008
DAT-200 Demo 1: Going from C# 2.0 data access to LINQ
DAT-200 Demo 2: Exploring LINQ to SQL Data
DAT-200 Demo 3: Working with XML Data
DAT-200 Demo 4: Working with XML and ASP.NET