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.
play the poke flute
you'll need the poke flute
Poke flute channel
Go up to it. Turn on your radio to the poke flute and then press A
In your radio, all you do is go to the top of your radio with the little dot and then it will say poke flute and then you can get that awsome snorlax that is blocking diglets cave. (but the poke-flute channel only works in Kanto not in Jhoto)
move the tuning dot to the top of the circle anywhere in kanto
The Poke Flute wakes up sleeping Pokemon, and was a key item in Pokemon Red, Blue, Yellow, FireRed, and LeafGreen. It could be used in or out of battle. The Blue Flute, however, as far as I can tell, only wakes up one Pokemon. I hope this helped.
diglett cave you have to wake the snorlax first with the poke flute radio channel
you have to get the poke flute poke gear radio station and play it next to snorelax
You can find the Poke Flute in the Pokemon Tower. After you free Mr. Fuji, he will give you the Poke Flute.
You go to lavender town and ask the important-looking guy standing by the tree
use the little circle and go to the top of the radio then you will here the poke flute