If you have a WAN and/or dial-up users, consider trying SourceOffSite from www.sourcegear.com. It absolutely rocks over slow connections.

A problem still exists however in that VFP stores info about the source control provider in project file, so mixing and matching source control providers can be tricky.

If control the files from outside of the VFP project this is not an issue, but if you use the "Update Project List" option within VFP (which is extremely tenuous anyway) to keep the .PJX files in synch among developers, you'll have some issues.

I recommend either - having everyone use SOS instead of VSS or controlling files outside of the VFP IDE. We wrote a program to synch project files for various programmers outside of source control, so it wasn't an issue for us. I'll share it at some point, but it's not ready yet...