Microsoft's Visual Basic Team has released a new Visual Studio Power Pack called Interop Forms Toolkit 1.0. This toolkit allows developers to embed VB.Net forms inside a VB6 application.
Unlike the Migration Wizard, this approach allows developers to convert and upgrade their VB6 applications one form at a time. Preliminary tests indicate that it can be used as easily as any other VB 6 form stored in a DLL. The only issue that has arisen thus far is that MDI Children do not seem to be supported.
Two possible migration strategies can be taken depending on your needs. One option would be to replace one form at a time until only VB.Net forms remain. The other is to keep existing functionality in VB6 and only use VB.Net for new forms.
Currently this toolkit does not directly support C#. The main issue is the automatically generated classes needed for interoperability are only produced in VB format. C# developers can hand-code these classes or modify the toolkit's source code.