There's already a lot for VB6 programmers to learn in moving to VB.NET. Why not let them use the VB functions at first, but do teach them the .NET framework versions. Later they could switch to the .NET framework functions, particularly if they are likely to need to use C# too.
EDIT (much later): two renowned VB gurus take opposing views!
- Francesco Balena (in his popular book Programming Microsoft Visual Basic 2005: The Language) recommends ex-VB6 developers learn the .NET syntax as soon as they feel comfortable with the new language and avoid using methods and classes in Microsoft.VisualBasic namespace if possible [p. 100]. His point is that in general native .NET methods offer better flexibility and learning them is an investment in case you later need to use C# or another .NET language.
- Dan Appleman (in his popular book Moving to VB.NET: Strategies, Concepts, and Code) recommends you feel free to stick with the native Microsoft.VisualBasic namespace avoiding only those in the Microsoft.VisualBasic.Compatibility.VB6 namespace [p. 265]. His point is that Microsoft.VisualBasic is a core part of the .NET framework.
