Things You'll Need
Instructions
Attach the Action Replay to your game, and then turn on the device.
Navigate to the "Enter Code" menu.
Enter the following code into the Action Replay device.
94000130 FDFF0000
B21C4D28 00000000
B0000004 00000000
94000130 FEFF0000
00000890 01ED0001
D0000000 00000000
DA000000 00000892
DC000000 00024620
C0000000 0000000B
D7000000 00000000
DC000000 00000006
D2000000 00000000
Uncheck all other cheats on the Action Replay Device, then start the game while holding down the "L" and the "R" buttons at the same time.
Open your bag while holding down the "L" and "R" buttons at the same time. If you do this correctly, it will show that you have 493 Master Balls.
Throw away Master Balls so you have the same number of Master Balls as the National Pokedex number of the Pokemon you are trying to catch. For example, Ivysaur has a National Pokedex number of two. To catch an Ivysaur, you would need to throw away 491 Master Balls so that you have only two remaining.
Walk into the nearest tall grass while holding down the "L" button. Your next Pokemon battle will be with the Pokemon that you selected.