Here are some useful cheats! I'll add some more later!

Make a pokemon level 100! (This may delete your game.)

• Press start and go to the item list.
• Go to the seventh item and press select for 5 seconds
• Go to fight a wild pokemon
• Press select at the ability u dislike
• The ability will change to strange ability that your pokemon shouldn't have
• Beat your enemy and your pokemon will become level 100!
• Go to a pokecentre if it messed up the HP bar and abilities of your pokemon

Getting a free bike:

• Goto Vermilion City, there is a Pokemon fans club.
• Listen to what the President says, he'll give you a Bike Voucher.
• Take it to the Bike Shop in Cerulean City and u will get a bike for free!

Whenever u make an attack hold in A and your attack will be stronger.

Stand on a tree

This is a cheat for standing on trees. First you go to a tree and cut it down, stand on the square that you cut the tree on, save the game and shut it off, then start the game again and you will be standing on the tree.

The Pokemon Daycare's secret system

Pokemon in Daycare gets 1 EXP point for each step you take.

Cut grass

Use cut in the grassy areas where you see pokemon, it will cut four squares of the grass a time. You can use this if your pokemon are almost dead or if your just sick of fighting.