>I'm splitting a large project into several smaller projects in the some solution
>I note that the app.config is associated with a project.
>All tasks begin at one project - others are called based on menu selections
>What's the best way to handle the app.config?

As Bonnie states you only need the one app.config file at the EXE level. In fact any other app.config file that exists in a DLL project is completely superflous - it's never used at runtime.

If you have app.config's in other projects they may have been automatically generated by, for example, one of the VS Data or WCF wizards to contain connection string info and suchlike. In that case you may need to copy/paste the relevant sections to the main app.config file so that they are available at runtime.
I've seen ideas for a few schemes which will enable access to DLL level app.confings at runtime but they tend, by neccessity, to be complex - usually a simple copy/paste as above is a one-off operation.

HTH,
Viv