On emarld you can duplicate pokemon can you duplicate on heart gold and soul silver? If you can were and how?
The easiest way that I've found in the original games is to catch a Ditto, then put the pokemon that you want to duplicate in the day care place with the Ditto, then wait. Come back later and you'll get an egg from the old man.
I think you mean an EXACT copy? In HG/SS if you transfer a poke'mon to the pokewalker then turn off your game when the game is saveing it will be on the game AND the pokewalker though I think the game deletes the clone when you return from the stroll