After Beating Clair in her gym (and after beating Team Rocket at the Radio Tower) surf behind the gym to the Dragon's Den. Surf down and across a whirlpool, and go into the building. The Elder will ask you some questions, then Clair will show up and give you the badge. When you get near the exit, Clair will be waiting and give you Dragon Pulse.
If you want to, after getting the TM head back to the Elder and he will give you a Dratini, which I think is at Level 15.
Go to the forth gym!
You will have to defeat Bugsy in Azalea Town. He has bug-type pokemon.
In Mahogany town right from Etrack city
it is bugsy the bug type leader
blackthorn city
It is your rival from Pokemon fire red and leaf green versions.
you have to get the cianwood gym badge and the olivine gym badge
There are 16 badges in total, 8 from Johto and 8 from Kanto.They are:Zephyr Badge - FlyingHive Badge - BugPlain Badge - NormalFog Badge - GhostStorm Badge - FightingMineral Badge - Ground / Steel / RockGlacier Badge - IceRising Badge - DragonBoulder Badge - Rock/GroundCascade Badge - WaterThunder Badge - ElectricRainbow Badge - GrassSoul Badge - PoisonMarsh Badge - PsychicVolcano Badge - FireEarth Badge - (last gym leader, blue, has no type i think he has a ninetales, a scizor, a rhydon, and other stuff.)
you get it in ilex forest after you get your 2 badge! hope this helps
go to the sprout tower in the town where you get the first badge at night.
in Goldenrod city
It is in Ecrutuk city the leader is morty who uses ghost type Pokemon