To get the pokeflute, go to
Lavender Town and go in the tower and face everyone there *Gary here, get ready* and you notice there's a ghost on the top floor so you can't advance. Then go to
Celadon Townand go to the Game Corner and go to a poster on the right. PRess A and defeat the leader of Team Rocket Givianni<-spelling? and get the tea from the women, then give it to the security guard who is "thirsty". Advance to your right and defeat everyone *there's Gary here, so get ready to face him*. I forgot where you get the silph scope though, but figure it out yourself. Go to the Pokemon Tower in
Lavender Town and go to the highest floor. Face the Marowak and defeat it. Defeat the Rocket Grunts and talk to the old man, then he'll give you the flute.