go 2 this website http://www.cheatcc.com/ds/pokemonp.html
You cant enter cheats on Pokemon Diamond, the only is on a game shard or by mystery event maybe.
type them in
you don't
You don't xD
There are no cheats for gameboy, althoughthere are for visualboy.
on action replay or m3dsreal
you need an action replay
no
I think they have made cheats for generation V I dont know if its specifically pokemon white that those cheats are for, I suggest searching: "pokemon white (enter what cheat you want) cheats.
yes action replay but you buy it at a store
go to the old lady in battle tower in battle fonter and she make you enter codes.
well you buy a cheat ds game at futershop and enter it and it will have the cheats