In Safari Zone
Go next door to wally's house and talk to his dad, he will give you surf.
You can find the Poke Flute in the Pokemon Tower. After you free Mr. Fuji, he will give you the Poke Flute.
i don't know where but i do in pearl/diamond/and platinum you need surf(also a Pokemon that knkows surf) then u surf around that aena with the windworks then you'll find it there and other poke balls too
by calanave with poke radar
celadon department store
In Pokemon SS/HG, to catch a red gyrados,have surf and go to the lake of rage. if you are at a certain point in the game, there will be a red gyrados thrashing in the middle of the lake. surf over and talk to it to invoke a battle, and use a poke ball of your choice after weakening it.
you will find it in the safari zone, in a poke ball.
when you find the Secret House in the Safari Zone
You go into the cerulean cave and find your way through it, buy lots of max repels. take a Pokemon with Surf, rock climb, rock smash. when you find mewtwo weaken him until he gets red health, paralyse, sleep him and throw poke balls at him :)
The Poke Flute is a radio station you can get after you receive the EXPN Card from the Kanto Radio Station in Lavender Town.To access the Poke Flute station, go to your radio and move the receiver icon to the top middle area.to get the red flute go to the lake of rage and to the west
In Johnto region by the 7th Gym when you surf.
If you fly to the poke centre near rock cave, then travel up to the river, surf down to the end, you will find a power plant. Enter it, and at the end of the pathways, you'll find Zapdos.