Enter codes at the cheat code screen in the options 

Effect:                          Cheat Code:
All people in multi              Party
Assassination Mode               SCOPE 
Baron Samedi for Multiplayer     VOODOO 
Christmas Jones for Multiplayer  NUCLEAR 
Countdown Level                  BLASTOFF
Demolition Mode                  TNT          
Equinox Level                    VACUUM     
Explosive Scenery                BOOM 
Faster Laser                     PHOTON
Goldeneye Strike                 Orbit 
Goldfinger for Multiplayer       MIDAS  
Jaws for Multiplayer             DENTAL 
Larger Sniper Rifle Clip         MAGAZINE
Max Zorin                        BLIMP
Miss Galore for Multiplayer      CIRCUS 
Oddjob for Multiplayer           BOWLER
Pick level                       PASSPORT 
Protect Mode                     GUARDIAN 
SCARAMANGA for Multiplayer       ASSASSIN
Stronger Tranquilizers           SLEEPY
Teamwork Koth Mode               TEAMWORK
Tuxedo for Multiplayer           BLACKTIE
Uplink Mode                      TRANSMIT 
Unlock Sniper Level              MELTDOWN
Unlock Golden Gun                TARGET
Unlock Golden P2K                Q LAB(Must have the space)
Xenia for Multiplayer            JANUS 
Unlock Renard for Multiplayer    HEADCASE

Unlimited PP7 ammo:
When you are playing level 12 on 1 player get a gold medal with all 007 icons.


Shelby Cobra on the Vanquished Level:
On the Vanquished level pause the game and HOLD L and press 
Right, Right, Left, left, Up

Submitted by ryan8190, TLbiker12, and an unknown person