What is the best pathway to achieve this?
I know that VS2005 contains an upgrade mechanism. Do any later versions of VS contain this?
Microsoft has devoted a site to VB6->.NET migration.
They recommend a Free tool from ArtInSoft.
However I'm not sure I'd like to maintain a .NET application written in VB6-style. But on the other hand a tool could give you a good start and you can refactor the result where the tool does not produce code of your liking.