After you beat Chuck(5th gym leader) on Cianwood island, i woman will talk to you and give you HM02.
I believe it is either HM6 or HM7.
You don't you have to use an Hm on a Pokemon
yes you can find that out in soul silver when lance flies on his so the answer is yes
you can find it anywere you have to ride you bike to it you cannot fly it will move farther away just if u see it on say... route 33 then go to route 34 and it will move closer to you
yeah
near enterna gym in the trees you will also find a green Dialga lo
go to jocose town
It depends on who you ask. Fly isn't a god awful flying type move, but there are better ones to be had. If it were me, I'd catch a throw away Pokemon and teach it Fly, that way I wouldn't have to waste a move slot on one of my more liked flying types.
Fly back to Goldenrod City and defeat Team Rocket.
HM 02 Fly is with the woman outside Cianwood City Gym.
first you have to beat the Pokemon league then you have to get a magnet train pass and then you will find steven in vermillion city and he will tell you that latios has come to kanto and after he leaves check your pokegear map and a latios icon will be there and that's where you will find latios (he will move if you fly or approach him too fast)
You have to defeat the Cianwood gym Leader, when you walk out of the ggym his wife will give the HM Fly to you