The best place is direct from Ford's website. Go to
Ford - Cars, SUVs, Trucks & Crossovers | Ford Vehicles
then look for owner info or something like that. Register with your VIN and all sorts of goodies await you.
We also have some of the owner guides right here on TheDieselStop, hidden in the '94-'97 FAQ. But the last year we have most of the "glovebox" manuals is 2003. However, nothing changed from 2003 model year with the 6.0L engine to 2004 with that same engine, so if you don't want to wait on Ford's website, then get the 2003 scheduled maintenance guide, Owner's Guide, and 6.0L diesel supplement right here:
2003 Downloads - 1994-1997 Power Stroke FAQ