OSX + Terminal.app + Emacs + make command key operate as meta

I'm on OSX Lion

I running emacs inside of Terminal.app

I want command-x to result in M-x (and in general, command -> M)

I have tried the following solution and they're not what I want:

• mapping command to Meta globally in system preferences

• mapping option to Meta only in Terminal.app

• Command key to Meta in Emacs

What I want, is only inside of Terminal.app (or only inside of emacs), to bind the command key to meta. How do I achieve this?