ye agree with water pokemon master...check the site before posting and this should really be in the help forum.
but just to be helpful, the link for all g/s/c gameshark codes is at this link: http://dynamic3.gamespy.com/~psypoke/gsc/gsgameshark.php
i believe the quantity modifier for slot 1 in item pack is
01xxb8d5 where xx is a hexadecimal number for the quantity.
edit: oh ye and the duplicating cheat (not really a code) is where u attach an item to a pokemon. save in front of pc. deposit pokemon, change box, turn off gameboy before it finishes the "Do not turn off gbc" message. turn gbc back on to find that the pokemon u deposited is still in ur party, but there is a duplicate of it in the box u deposited before switching. and on top of that they both have the item u gave to it to hold, duplicated.