First go to cheats and then cheatlist. Then go to gameshark and put the following code for the following Pokemon.

Ho-oh
92BB8BD9629E2D58

Celebi
A3AFC93BCAE30FEC

Lugia
E57F3F7864F944D0

Can someone tell me how to get Feebas. I only need two more Pokemon to finish my pokedex.