In Heart Gold, after beating all 16 gyms you can re-battle Pokemon in order to re-battle Misty. Go to the city her gym is in then go up until you see the bridge. Then take a right. You will see a trainer; battle him then keep going and work your way through the trees. Keep going to the right until you reach some stairs, go up the stairs and Misty will be there. Talk to her and she will give you her phone number! (I don't know if you have to get Janine's phone number first but if you do then I will tell you how.)
Here is how to re-battle Janine. Go to the thing that leads to the start of Victory Road where the two people are blocking Mt Silver and Kanto region. Well after beating all 16 gyms Janine will be there. Talk to her to get her phone number.
Go north of town to Cerulean Cape (up near Bill's house) and crash her date. She'll get so mad at you that she'll insist on a battle.
With pikachu. Electric smokes water. Just use thundershock
misty will be a gym leader in HeartGold and SoulSilver
Beat the rest of the gym leaders first.
it is in misty's gym press a on the life savers
Travel to the end of Route 25 and she will be standing there.
You must go and battle Misty. Once you defeat her, she will give you a badge. You have then defeated the gym.
He hides the generator in the Cerulean Gym beside a swimming tube at the back of the gym (Around where misty would have been in the Gym)
you need to first go to the power plant and find out that there was a thief and then find him in Misty's gym and then interrupt misty's date on route 25
she is at cerulean cape
After you beat the Cerulean Gym it is up on the cape where you find Misty. You have to see it at other points during the game though
Misty is the gym leader of Cerulean City.
in the gym
I don't have heart gold but its Vermilloin city next gym leader is Lt.Surge he has electric Pokemon No,Brock is next,ok?