>I've heard horror stories of the results of loading VFP6 on the same machine with VFP5. I'm about to take that step. I would appreciate any advice/comment.

Really depends on what you're doing. They can coexist without problems. However, VFP 6.0 installs new versions of several ActiveX controls that can affect your programs. There is a tool on the VFP web site to automatically change the references in your source code.