cheats and codes
99 Items
First, return back to Viridian City and talk to the man who taught you how to catch a Weedle [he is near the gym where you face Giovanni]. Reply '' No '' to his question, then watch him catch a Weedle. Then, place the item you want 99 of as number six from the top of the items list. To put the item at six you must press select while pointing to an item, then move the arrow where you want the item to go and push select again. Both items will switch places. Now fly to cinnabar island and start surfing along the east coast of cinnabar. Soon you will face a messed up pokemon with a name called M. Run away from M, but dont try to capture it because it meet ruin your game!!! Once you run away look at your items list and you will have 99 of your sixth item.

Fight Level 100 Pokemon
To fight level 100 pokemon you must proform the 99 item cheat above, and then after encountering M, keep surfing around for pokemon. You will soon encounter level 135 pokemon and above!!!
Missingno//#000
First you must have a pokemon with surf. Go in the first door inside the pokemon lab on Cinnabar Island and trade with one of the trainers in there. Then surf along the east coast of Cinnabar island, half on water, half on land. Eventually you will fight a bird called Missingno. The forth legendary bird!!! it does lots of damage but is easy to defeat. It looks like a mass of dots flying around, just throw balls at him to catch him. Be warned, having this pokemon can crash your Hall of Fame and mess up the graphics. Beleave me it happened to me, but it only messed up my hall of fame. Older gameboys [ not pocket or color ] have more of a chance of there game messing up.
Clone Pokemon
You need a friend for this cheat. Trade the pokemon to be cloned and have your friend get a pokemon they don't care about. Trade them, and make sure the person getting the weak and common pokemon can see the other screen. When the receiver of the good pokemon's screen says ''waiting'', turn off the gameboy thats getting the bad pokemon. When the other one says trade completed turn that one off too. When you turn the games back on, you should both have the powerful pokemon, but the weak pokemon will be lost. Warning this could delete the powerful pokemon!!!
Go To Sleep.....Now wake up
If you have pokemon who have Rest or TM44, your pokemon can restore all of his/her hit points[HP], in a span of 2 turns. Simply use Rest during battle [the pokemon will fall asleep], then during your next turn, play the poke flute and your pokemon will wake up!!!
The Legendary Birds
of all the legendary birds I've found Zapdos is the easiest to capture [which isn't saying much!!!] since it is possible to capture it when it has nothing wrong with it's status [such as sleep or paralyze] and it is possible to capture it when it's health bar is more then just a sliver. Once you capture Zapdos you can use him to quickly lower the health level of Articuno and Moltres [for these last two I needed to reduce thier defence or make them go to sleep to even hit them with a poke-ball]
Better Chance To Capture Pokemon
When you throw a poke-ball hold UP and press down the A button as it closes on the pokemon. The poke-ball will shut tighter and it will be easier to catch the pokemon. This trick will work best with the ultra ball.
Harder Hitting Attacks
This cheat is sorta like the ''better chance to catch pokemon'' code but it's for attack. Just hold A button while your attacking and it will do more damage than if you didn't hold A.
Phantom PC
That's right, a phantom PC!!! Go to Celadon City, then go south untill you are by the Alley where the Game Corner is. Walk EAST untill you are standing next to a bush. CUT the bush down and go SOUTH to the first building to the WEST....this is the people motel. Enter the motel and walk NORTH untill you hit the shelf, then walk EAST untill you hit the wall. Now walk DOWN 2 spaces, then walk UP 1 space. Now press A and select something to do!!!
Even The Odds At Game Corner
In the casino above the guy with the glasses that you usually find in gyms is a slot machine with great odds. The way i got a Porygon was simple but still long. Save the game when you hit the jackpot. After a while the game is fixed and you will either get multiple wins, or hit the jackpot-doing that you eventually start to win several hundred at a time. By hitting the A button rapidly it sets a pattern to make sure you now when the jackpot comes up-the slot machine starts to slow down.
Moon Stones
There are five Moon Stones, three of which are visible, two of which are not.
1] In the upper-lefthand corner of the first floor of Mt. Moon
2] In the basement of the game corner
3] In the bottom-right corner of route 2 [ cut ]
4] In Mt. Moon, before the Supernerd's platform, there is a corridor 4 spaces long and 1 space wide, go to the end of it and press A
5] In the pokemon Mansion on Cinnabar Island, go up to the right side of one of the pillars on the right-hand side near the entrance hit A.
Fight Safari Pokemon Elsewhere
To fight and capture Safari Zone pokemon outside of the park, you must first go into the Safari
Zone. Let the time run out when you're standing in a patch of grass which holds the pokemon you want to catch. Step back outside and use FLY to fly back to Cinnabar island. Using SURF, surf up and down the east coast, you then should battle pokemon from the Safari Zone!!!