after beating the seventh gym leader go to the basement of golderod city. Their is a man by a camera in a team rocket uniform. talk to him and he will give you a team rocket uniform. then talk to the team rocket grunt blocking the stairs of the radio tower. (sorry if I spelt the city wrong. it's in the same place as the radio tower)
Chat with our AI personalities
It is in the Radio Tower in Goldenrod city
Go to the lavender town radio tower and talk to the old man inside
use the pokeflute but if ur in heartgold or soulsilver, move the dot on ur radio to the top of the circle (pokeflute channel)
You can find the radio tower director in the Goldenrod City Tunnel.He is down a few floors by som boxes.Talk to him and he'll say a few things and walk away.After that you can find him in the Radio Tower.This is form SoulSilver,because I don't have HeartGold.But I know SoulSilver and HeartGold are the same except about the types and accurances of Pokemon appearing.I hope I helped!
its in Lavender town