Raikou? I think you mean Raichu. To get a Raichu, just use a thunderstone on a Pikachu and it should evolve into Raichu. To get the thunderstone, go to the Celedon Department store or find one at the power plant.
In the wild.
you cat a
Raikou is only found in firered and leafgreen if you chose squirtle as your starter Pokemon. Or you can get the purified raikou from Pokemon colosseum.
Get another from leafgreen or another firered or get one from Pokemon colosseum.
Trade from FireRed or LeafGreen.
Since it is a wandering pokemon, there is no definite place to find it. By the way, I believe it is Where IS Raikou in Fire Red.
You catch raikou in vermilion city in the smallest patch of grass
Raikou is a legendary dog Pokemon. It is not in any specific location in Pokemon Fire Red. Instead, you can find it roaming Sinnoh.
You cannot catch Raikou in Pokemon Diamond and Pearl. To get Raikou in Pokemon Diamond and Pearl, you must trade for one from Pokemon HeartGold and SoulSilver where it can be caught or transferring from Pokemon FireRed and LeafGreen.
Rare Pokemon that can be caught in firered are: Moltres, Zapdos, Articuno, Mewtwo, Raikou/Suicune/Entei (depends on which starter Pokemon you choose).
Capture Entei/Raikou/Suicune.
Moltres, Zapdos, Articuno, Raikou/Suicune/Entei.