nothing
The only legendary eggs you can get in SoulSilver are Phione eggs. You get these by breeding Manaphy at the day-care with a Ditto. You get a weird looking egg which hatches into Phione. Phione doesn't evolve into Manaphy.
no you can trade soulsilver pokemon to black
he is not in Pokemon soulsilver or Pokemon heartgold
I bought mine at Toys R Us.. I know it sounds weird, but they have good games there.
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
SOulsilver
You CANNOT LEGALLY download Pokemon Soulsilver.
You can't catch bastiodon in Pokemon soulsilver.
You'll need to trade for it from Pokemon HeartGold. It is not avilable in the wild in Pokemon SoulSilver.
there is a mew in Pokemon soulsilver but you need to catch all leadndery Pokemon including event Pokemon
You cannot battle between a Pokemon Black game and a Pokemon Soulsilver game.