How can I change the meta key on OS X Lion's Terminal.app? Is there any way to use "Option" as the meta key in OS X Lion's Terminal.app? The checkbox that was present in Snow Leopard is nowhere to be found.
Are you sure that it's not to be found?  If I look at Preferences → Settings → Keyboard, the checkbox for Use option as meta key is at the bottom.

I am on 10.7.1 so it may be something overlooked in the GM of Lion and fixed in the first patch.