You can most certainly make DLL's in VB6 and VB.NET. In VB6, the
DLLs utilize COM, so any language that supports COM
(VB6, .NET languages, C++, etc.) can use VB6 DLLs.
.NET languages, however, (perhaps with the exception of C++.NET,
I'm not sure) compile to special DLLs that only other .NET
applications can import.