These codes are tried and tested with the Gameshark, and they work. However, gameshark codes can do anything from freezing your game to corrupting it's save file. Although there isn't a very big chance of that happening, there is still a risk involved, so please use these codes at your own risk!
8111a67430ff 8111a676ffff - All quest/status items.
8111a66c7777 - All weapons/equiptment
8011a6490005 8011a64f000d 8011a6550013 - All spells.
8111a5fe0140 - All heart pieces
d01c84b50020 811daa9040cb - Levitate mid-air (press L)