Most evolving stones can be dug up from the underground tunnels. I'm not sure where to find them in the game. I do know though that you can find a thunderstone at fuego ironworks.
A few stones can be found elsewhere but majority is underground ( NO TRADE STONES )
evolving evee at night
You can find stones undergrounds.
You can only get Snorlax by evolving Munchlax.
In Iron Island or underground
evolve nidorina and nidorino
The evolution stones in Diamond/Pearl/Platinum are the water stone, fire stone, thunder stone, moon stone, leaf stone, sun stone, dusk stone, shiny stone, and dawn stone. (Sorry if I missed one) And even though this is the opposite answer, the stone to keep Pokemon from evolving (with or without evolution stones) is the everstone. Hope this helps! :)
You can find stones Underground. You take the explorer kit and then go underground.
No, a Water Stone will not stop a Pokémon from evolving. An item called an Everstone will stop Pokémon from evolving however Water Stones are used for evolving specific Pokémon. Water Stones can evolve Poliwhirl into Poliwrath, Shellder into Cloyster, Staryu into Starmie, Eevee into Vaporeon, Lombre into Ludicolo and Panpour into Simipour.
Iron Island.
The Underground
there is none sorry