Stir together first 5 ingredients; cover sauce, and chill 8 hours.
Soak wood chips in water at least 30 minutes.
Prepare charcoal fire in smoker; let burn 15 to 20 minutes.
Rinse chickens, and pat dry.
Sprinkle each chicken with ½ teaspoon salt and ½ teaspoon pepper.
Place 2 lemon halves into cavity of each chicken.
Drain chips, and place on coals.
Place water pan in smoker; add water to depth of fill line.
Place chickens on lower food rack; cover with smoker lid.
Cook 1 hour and 30 minutes or until a meat thermometer inserted into thigh registers 175°.
Serve chicken with sauce.
