I would look into using a terminal server solution if I were you.

Here is a snippet from MS about TS:

Windows Server Terminal Services
Terminal Services provides technologies that enable access, from almost any computing device, to a server running Windows-based programs or the full Windows desktop. Users can connect to a terminal server to run programs and use network resources on that server.


>I want all users to be able to add data to the database. The system is already written and is totally foxpro - multiuser. Each site has there own server and I was hoping I could do something without much changes and without user having to use pc anywhere or vpn solution.