His name is Blue, and he is on Cinnabar Island. Show him the other 7 Kanto Badges and he will go to the Viridian City gym. Then, go to Viridian City and battle him at that gym.
The eighth gym leader still awaits, as well as the whole of Kanto.
All you have to do is get to Viridian City.
Blue (The eighth gym leader) is waiting on Cinnabar. He won't battle you unless you've beat the rest of the gym leaders
Not enough info: which gym leader?
Janine I think
You beat the 6th gym leader.
he is Brock. hes in pewter city.
Clair and she is the leader of blackthorn city or if you mean the kanto leader its blue/Gary ashes rivle
The SS Anne is not in HeartGold or SoulSilver however when you arrive in Kanto you'll arrive in Vermilion City so you go and challenge the Gym Leader there.
Johto and Kanto
You go to cinnabar island and he will be there, but to battle him you have to beat Blaine he's at the sea foam island go up the ladder. Hope I helped!
To get a Pikachu in Pokemon SoulSilver, you must go to Viridian Forest, which is in the Kanto region.