No it is not possible.
You can't!
All in regional dex
no to trade between leaf green and sapphire or ruby u must beat the Pokemon league then go to the seven islands and find the ruby and the sapphire gems to be able to trade
You can with the action replay Pokemon modifier cheat.
There are No Cheats to this game
Gosh that to many steps.. google it! haha that always helps me. lol
I caught one through the right gate of Hearthome City
By beating the elite for then Beating the champion.
you beat the poke league by the way do you know any R4 cheats for diamond wich path
hes is the pokemon league champion
in kanto
Warp to cave on Mt. Ember by gameshark or action replay.