Where are the glow plugs on a 2003 ford 6.0 liter diesel?

On a 2003 Ford 6.0L Power Stroke diesel, the glow plugs are located on top of the engine, one per cylinder, directly in the cylinder head. They're fairly easily accessible once you remove the valve covers. However, accessing them requires some mechanical aptitude and appropriate tools. It's not a simple job for someone without experience working on diesel engines.