I copied the most in-depth answer, and corrected some spelling and grammatical errors.
"You can't catch Mew in HeartGold or SoulSilver. There are only three ways to get a Mew, first you get one from a Pokemon event, second you can get one in the Wii game 'My Pokemon Ranch' (Hayley gives it to you once you have met certain conditions) and then it would have to be transferred to Diamond or Pearl to HG or SS, and the third way is action replay (cheat codes). You can catch Mewtwo in Cerulean Cave.
First answer by ID1246280298. Last edit by Charleswoodard."
if you have any other problems, just look them up on Bulbapedia (bulbapedia.bulbagarden.net) Best of luck.
You gotta catch a corphish, use the superrod in the ponds by Petalburg or Oldale. Then level it up to 30, then it will evolve to Crawdaunt.
you have to trade spheres for it
Nothing much happens, but they may have been the last required Pokemon to complete the Sinnoh Dex. dude! that's so wrong, I tried it! I took it to the celestic town and went inside the cave and press a to the picture of 3 legendary poke mon. It will shine and many thing happens which is really hard to say
Japanese people you can tell from the names in the End Credits
Cheren gives you the HM in Route 6.
yes they do
go onto your poke gear and look for the radio icon
Go to the national park and from there you should be able to the pokeathlon dome in poke mon heart gold.
poliwag?
Out of Kurt's balls, the one that would work best is most likely the fast ball.
try a pokéball.... it might help.
there will be an event where you can catch arceus coming soon.
You gotta catch a corphish, use the superrod in the ponds by Petalburg or Oldale. Then level it up to 30, then it will evolve to Crawdaunt.
You have to download the azure flute from mystery gift.
You catch the legendary Poke mon. In platinum you catch GUIRETEINA, in pearl you catch PALKIA, in dimond you catch DIALGA
Like Gastlys & stuff...
In Pokémon Gold, you can catch Gligar in Route 45.