listen to me . i put the codes on the (cheat list) then it did not work
if u want to help me tell me how to use it (step by step)ok and if u want any thing from me i am ready (iam super player) but not super cheater yet

First load your game, and get to a handy spot for your cheat (for instance, if using encounter codes, then stick around by a grassy patch)
Step 1:
Cheat Menu > Click "Automatic save/load cheats" if its not already checked.
Step 2:
Cheat List
Step 3:
Gameshark
Step 4:
Name the cheat
Step 5:
Enter the cheat code
Step 6:
Click okay, and the cheat appears in the list, make sure all the boxes are checked (do this for as many cheats as required to have the desired effect, for instance, if using pokemon encounter, you need to enter the Master code, the Encounter code, and the Pokemon code seperately. Note: Only one code/ code combo may be checked at once)
then click okay
Step 7:
Do what you need with the cheat, and then go back to the cheat list and un-check it (you must do this BEFORE SAVING)
Step 8:
Save your game

Voila.
Any more trouble just ask.