As mentioned on the Microsoft site, the training kit offers the following benefits:
- Learn how to build web applications that exploit the unique features and capabilities of SQL Server 2008.
- Provides a comprehensive set of presentations, demos and hands-on labs
- Designed for web developers who are already familiar with SQL Server application development.
- Easy to download and install and works on free editions of SQL Server 2008 and Visual Studio 2008.
Get more details about the SQL Server 2008 Developer Kit here