You get mew from a event... but unfortnately there aren't any at the moment. You could then load it onto a copy of Pokemon diamond/pearl/platinum and conquer sinnoh with mew.
If your playing Pokemon diamond/pearl/platinum they you could try the gts but i think you need to have seen the Pokemon unless you know anyone with a hacked one... usually the pokedex entry is added.
Also a recent way i rescerch was that you can get a mew that know's synthesis (yeah the grass type healing move) from Pokemon ranch and send it from wii to ds also you can a phoine this way as well... note you must complete Pokemon ranch before you try to get mew... there the only official ways of getting a legal mew...
otherwise you could hack one...
physic
Cerulean Cave.
you go out and go back in later to get mew
NO!You can only catch Mewtew in Cerulean cave
no,mewtwo is not in Brawl. His replacement is along the lines of lucario...
Articuno, Moltres, Zaptos and mewtew and Missingno
Mewtew is not on super smash brothers brawl; only on Super Smash Brothers Melee. Lucario is sort of Mewtew's replacement on Brawl, though there are quite a few differences between them.
You can find Mewtwo in cerulean cave when you go to the Kanto region.
Mewtwo is not in brawl so that means you can't unlock him.
You cannot catch Mewtwo on Emerald. You have to trade for it on Fire Red or Leaf Green.
probably mewtew,ho-oh,lugia,dialga,palkia,acerucs, but mostly celbi.
You're an idiot. Mewtwo is the worst character besides Pichu.