You will have to trade it from Diamond, Pearl or Platinum to get one.
Yes creselia is is in Pokemon Platinum.
you can find creselia on moonlight island but i dont know about darkrai.
Probably creselia
You cannot breed Cresselia. Cresselia is a legendary Pokemon, and you cannot breed a legendary Pokemon.
no you can trade soulsilver pokemon to black
he is not in Pokemon soulsilver or Pokemon heartgold
POKEMON SOULSILVER come with a poke walker and the Soulsilver game
Pokemon soulsilver and Pokemon heartgold are basically the same game just different versions but i do recommend buying Pokemon soulsilver
my friend told me you have to get the national pokedex and then go to canalave dock and then ask for a ride. Then ask to go to (full\new) moon island. Then you can catch creselia!!
SOulsilver
You CANNOT LEGALLY download Pokemon Soulsilver.
You can't catch bastiodon in Pokemon soulsilver.