The 2003 Dodge Dakota 4.7L V8 spark plugs are located on
the top of the engine, between the valve covers. You'll need to remove the plastic engine covers to access them. They're arranged in a V-formation, following the layout of the cylinders in the V8 engine. There's a plug for each cylinder (8 total).
Because of the close proximity and somewhat complex layout, it's advisable to consult a repair manual specific to your 2003 Dodge Dakota 4.7L. A diagram showing the precise location of each plug will be invaluable. These manuals are available online and from auto parts stores.