You can't get mew in firered or leafgreen.
Mewtwo? Plus you cannot get Mew in Leafgreen or Firered.
Mewtwo, yes, if you have a FireRed or LeafGreen with Mewtwo.
There is no Mew in FireRed or LeafGreen.
No. It's a cheat. Mewto, yes.
if you want a cheat on how to get a mew on your first trip to cerelean city go to youtube and search how to get a mew in leafgreen or firered. or simply type mew(never tried that) ^^
No you caan only send it from firered or leafgreen
be a total doosh
Some people say to nickname your starter Pokemon "Mew" and it will play as mew for the rest of the game but I never tested it...
The Missingno/Mew glitches are not in Pokemon Fire Red/Leaf Green.
No it doesn't exist.
No you'll have to transfer it from LeafGreen/FireRed or trade it from SoulSilver/HeartGold.