Legendary Pokemon Codes
You can enter codes to automatically obtain Legendary Pokemon instead of having to catch them in the game. First enter the master code: "0000BE99000A 1003DAE60007" using VisualBoy's built-in GameShark. The master code enables the use of other codes. Code for Legendary Pokemon are:
Mewtwo: 83007CEE0096
Mew: 83007CEE0097
Ho-oh: 83007CEE00FA
Lugia: 83007CEE00F9
Old Version Starter Pokemon
You can obtain the starter Pokemon Bulbasaur, Squirtle and Charmander by using the codes "83007CEE0001" for Bulbasaur, "83007CEE0007" for Squirtle and "83007CEE0004" for Charmander.
Battle Codes
Use the code "A83F9AD9A2F7" to prevent any random battles. This is like a permanent repellant item. Use "A67B84289866 D6DB22825699" to escape from any battle.
Leveling Pokemon
For 5000 immediate experience points, use the code "FEBB0A6A8203 087B9AD720EE." To obtain Rare Candies, which grant one level each, use "820258400044."
Safari Zone Codes
To prevent your time in the Safari Zone from ever running out, enter "663F08E44889." This is best used with the code for infinite Safari Balls, "4B294D4AE337." You can also use "660032045925 E2308E556465" to make Safari Zone Pokemon easier to catch.