Seems like an awakening from a long sleep. There's VFP9 for the Vista+ generation and you've not updated through 5 other foxpro versions (there was no VFP4). Be prepared that you'll now may get away cheaper and faster, than taking together what migration to each new version would have taken, but it's a huge gap between fpd 2.6 and VB.Net 2008.
In certain cases it may be possible to do this partially only. Eg keep the DOS app and data, implement parts of the application in VB.net and work on the same DBFs. But there are some code page issues (DOS vs. Windows), though it's technically possible to access older DBF version with VB.net using the OLEDB Provider of VFP. It's unlikely though, that you will be happy with the current table structures in an OOP application. It's likely you'll want a redesign of the database.
It's of cause possible, like it is possible with any system: By a complete rewrite. You'd perhaps migrate data to SQL Server and app to VB.NET, maybe VFP, that depends on who should migrate the system with which knowledge about the data, the application and the programming languages.
Bye, Olaf.