Database Journal has a good list of some upcoming SQL Server related live webcasts scheduled for July (on MSDN and TechNet):

Some that should be of interest for developers using ADO.NET:

• What I Wish Developers Knew About Writing Queries in SQL Server 2005
• What I Wish Developers Knew About Writing Applications for SQL Server 2005
• Enhancements to the SqlClient Data Provider (ref docs here)
• Implementing a Data Access Layer with the Visual Studio 2005 Dataset Designer (see this recent article for ASP.NET 'Creating a Data Access Layer')