Buy the next game
no
its not possible
It doesn't matter how many times you beat the elite four, celebi is not going to just appear.
The game does open after beating the Elite Four. You simply select Continue, and you will be back at your house after you have beaten the Elite Four and Champion. :3
with hax
in what game of Pokemon
You find him in meteor cave after beating the elite four.
FAP
By trade
by beating the elite four.
Face Red
When you defeat the elite four now you will go to the cave in Cerulean City.