Go to Mahagony Town.
He is in the cave on Seafoam Island, which is east from Cinnabar.
to battle Blue in Pokemon Heartgold you must defeat the 7th gym leader, then find him on cinnabar island. Talk to him, then he will go back to his gym for you to fight
You CAN NOT become a Gym Leader in Pokemon HeartGold and SoulSilver or ANY MAIN SERIES POKEMON GAME.
your Pokemon sould be at least a level 25
In Pokémon HeartGold, you can find the 3rd Gym Leader in Goldenrod City.
Obtain it from a gym leader.
The gym is in Blackthorn City.The gym leader is Clair.
He has many types.
try beating the gym leader
he is the vermillion city gym leader.
awww by beating the 7th gym
first get a ice type Pokemon then go threw the whole gym face gym leader and get the badge