In your pokeGear after solving the polblem in the power plant
There is no Poke Flute item in Pokemon Silver. Instead, the player can have their radio upgraded in Lavender Town. It will then play a station that can play the Poke Flute tune.
To get the poke flute on silver you need to go to the radio tower in lavender city, talk to the man inside and he will upgrade the radio on the poke gear. You should then be able to find the poke flute radio broadcast.
in the kanto
you can't get the poke flute on soul silver however you can get it on the poke radio to wake the sleeping snorlax blocking entrance to diglets cave.
move the dot to the top, you should find the poke flute channel
Wednesday (I think)
From a man in the Pokemon tower.
It should be on your Pokegear.
You can't really find the poke flute but its on your radio on your pokegear its a secret channel that you have to go all the way up on to get the station
you need to have a poke flute. by unknown
In poke platinum you get a black poke flute from Looker the agent
in frunt of diglets cave use the poke flute (it is on your radio)