As freelance advertising copywriters, Tina Rabb and Deborah Davies were selling supersonic sub-woofers and touting Tijuana getaways on everything from billboards to fast food tray lines when it hit them: They were using their expertise to persuade people to buy things they may not really need -- so why not use that knowledge to help churches get the most mileage from their billboards? Why not promote something people truly need in their daily lives -- the love of God?There are probably more than a million church signs and marquees in the United States, each offering an unparalleled chance to...