Infinite Items:
On disc 4 you can grab items, save, then load your game and the items will be there, and you can do this until you have as much as you need.

GameShark Codes

Infinite First-Aid Spray
8E93842F00000063

Never Reload Grenade
3A212D680000000F

Never Reload Machine Gun
53C77E780000000F

Thanks to Revolution readers Joseph Tuvera and Cameron Roy!