Export forms and code modules from within the VBA editor. Forms cannot be converted but their associated code can be exported
Create a VB 6 project and import the exported VBA items. Save the project
Open the VB 6 project in Visual Basic 2008. The new version of VB will recognize the VB 6 project and run it through a conversion routine
Create a new Visual Basic 2008 project per ArcObjects guidelines
Recreate the forms from the VBA project. Using the same field names will mean less work when converting the code. In the add-in framework, forms are hosted/managed by the DockableWindow object
Copy and paste the code from the converted project to the new project. Clean up warnings and review comments added by the conversion routine
Notes:
Windows forms cannot use carriage returns for the text in design mode; Set the text in the New() subroutine on the form object