With a regular, old-fashioned poke ball.
You have to get an action replay and battle one of the elite four
Mystery Zone
Great Marsh (Rare)
You can't catch bastiodon in Pokemon soulsilver.
Groudon Gulpin Vulpix Raquaza Bidoof Starly Magikarp Gyraddos Lugia Ho-Oh Latios Pikachu Charmander Sqirtle Bulbasaur Pidgey HEY NEW PERSON!! You can caych way more! Head over to a SoulSilver pokedex.
trade or migrate or action replay
in the poke walker path noisy forest its the second one i think that one u get first with refreshing feild.
catch it? no.
No, you can not catch Phanpy in SoulSilver. It is a version exclusive to HeartGold.
You cannot catch Heatran in Pokémon SoulSilver, you will have to trade for it.
You cannot catch Celebi in Pokemon Soulsilver, you have to transfer it from Diamond and Pearl (if you have it in those games).
From bulbapedia:HeartGoldSoulSilverSwarmRoute 3-Mudkipie