Utilize table-valued parameters to write less code and to achieve higher application performance.
Take advantage of the System.AddIn namespace to handle logic external to your application; don't get caught by Excel's one-based indexes; and make LINQ extension methods work with ArrayLists.
Take advantage of new features in C# 3.0 that let you treat code as data -- and save time over more traditional, imperative approaches to programming.
Use PInvoke to take advantage of Windows APIs that aren't part of the .NET Framework.
VB.NET gets left behind (again), this time by the Windows Live team.
Been missing the old VBPJ archives? You're not the only one.
Make sure developers don't sacrifice quality for the sake of finishing.
Microsoft's releasing some .NET 3.5 Framework swag: deployment guidelines and the source code itself.