I have two independent projects in my Visual Studio 2008 solution. Both has its own App.config. But in one project, I need one or two properties defined in another project\'
Something I like to do, especially when trying to coordinate ServiceModel elements between libraries and tests is to use configSource to fragment the config in the target library and simply link/copy always the fragments in my test projects.
That way I only maintain in one location.
You could take it one step farther and simply have a common directory in the solution and link the fragments in all projects.