How to Obtain
Go to Cinnabar Volcano and talk to the guy with red wings in the house at the very back. He will have a feeling that Route _____/ _____ City will have a rare Pokémon. That Pokémon can be Rayquaza, Cresselia or Manaphy.
It can also be obtained from trading and the Pokemon Roulette. However, it is highly unlikely that wish_z will ever make a Rayquaza code because it will break the game.
Rayquaza can Mega Evolve into Mega Rayquaza. In Project: Pokemon however, Rayquaza won't have Mega Evolution implemented, as it may break the game.
Moves when caught
May vary depending on level found and can also be taught by Move-Relearner
Moves that can be taught using TM's