In every town there is a Pokemon centre.
the trade center is up stairs in the poke center
In Solaceon Town, right next to the poke center
Talk to a woman in Eterna city Poke center and she'll give you it.
Go to Eterna City and go in the house next to the poke-center and talk to the old man.
Buck's house is the one to the left of the poke center in the survival area.
go to the veilstone mart it is north-west of the poke-center
It`s just north of the poke center also has a big shiny diamond on the front.
you open a diamond with another diamond stick a ball in it ,put it back together and poke it!
get the Poke tech App Poke happyness
hoenn
its a mystery gift
action replay code to get unlimited every-poke-ball in Pokemon diamond?Read more: What_is_the_action_replay_code_to_get_unlimited_every-poke-ball_in_Pokemon_diamond