Mewtwo can be found in Mahogany Town where Pryce is.
In Pokemon indigo, which is online, you can find them in rooms, but i don't know about other games.
after Pokemon league in islands
go to map somwhere in routes gyms or elite four
only if u had firefox or firebug its a cheat and u can get any Pokemon i no how it works someone had a mewtwo by getting firebug and i saw the video
i dont even know lol, but i know with it you can get mewtwo and mew
ceruleon cave i hate to say it but whoever created this awnser was thinking of the Pokemon games for gameboy/advance. now i will tell anyone were mewtwo and mew are if they send me IC$10000 Pokemon indigo credits. my usename is burrmab
You can find Mewtwo in the Cerulean Cave.
You get Mewtwo in Cerelean Cave.
Entei can be found in Nimbasa City in Pokemon Indigo.
The following Pokemon should be unlocked: Zapdos: Get him in rooms Mewtwo: Get him in rooms Mew: Get him in rooms Garatina: Exploder, Cheat, Hack, Trade Ect. Dialga: Get him in rooms Palkia: Get him in rooms
Mewtwo is found in cerulean cave.
It's impossible to find Mewtwo in Platinum.