Hi Pablo
There are many Source Code Control system available on the market that work well witl Visual Foxpro. One these is Microsoft's Visual SourceSafe. If you are not familiar with these, they work like a public library. Only one person can check out a peice of the source code at a time. When they check it back in, a history of the changes are recorded. Also, if you are investigating a source code control system other then SourceSafe, be sure it is SCC compilant.
Greg Reichert