Borderlands Cheat Codes

Go to My Documents\My Games\Borderlands\WillowGame\Config\ and open WillowGame.ini. Search for the term and change it.

bResurrectAllPlayersWhenOneDies - set to "true" to ressurect all players when one of your guys dies.
bBossesRegenHealthOnReset - set to "true" so bosses do not regain health after dying.
bIgnoreFriendlyFire - set to "false" to be able to shoot your teammates and do damage (there's two of these)
bIgnoreNPCFriendlyFire - set to "false" to let NPCs do dmg to eachother
InventorySlotMax_Misc (choose number) - Raise Max Inventory
WeaponReadyMax (2 to 4) - Cap Weapon Slots
bDemiGodMode (set to true) - Demigod Mode (Invincibility)