Enter the codes in the Multiplayer/Ulockables menu. 

Unlock Recon Kit (QBU88)           Enter your3mynextt4rget as a code.

Unlock Special Ops Kit (UZI)       Enter cov3r1ngthecorn3r as a code. 

Unlock Support Kit (M60)           Enter try4ndrunf0rcov3r as a code.


Unlockables

Unlockable:              How to Unlock

F2000                    Participate in the Battlefield Veterans program.

USAS-12                  Check your multiplayer stats online.

QBU-88                   Pre-order the game (no longer optional).

Uzi                      Reach rank 4 in the online demo.

M60                      Sign up for the Battlefield: Bad Company 
                         newsletter.


WildCards
     Certain achievements in game.
     
Unlockable:              How to Unlock:

1 On 1 Air               In a Round destroy an air vehicle of the same 
                         kind without assistance

1 On 1 Land              In a Round destroy a land vehicle of the same 
                         kind without assistance

1 On 1 Sea               In a round destroy a sea vehicle of the same 
                         kind without assistance

2 Pair                   In a round get 2 of any 2 trophies

Airtime                  In a Round 2 seconds air time in a land vehicle

Armor Buster             In a round kill 5 armored vehicles

Beat The House           15 Grenade kills in a round

Cab Driver               In a Round 5 min as driver 
                         in a vehicle with passengers

Chopper Chopper Kills    In a round kill 5 air vehicles

Destruction Site         In a Round Destroy 50 Objects

Dueces Are Wild          In a Round Kill 2 Enemies of each Kit

Five Of A Kind           In a Round destroy 5 vehicles of the same kind

Full Deck                52 total kills in a round

Full House               Kill 3 vehicles of the same kind 
                         and then kill 2 vehicles of the same kind 
                         in a round

Gunslinger               80 kills with a handgun

Headshots                20 kills from headshots in a round

Parashooter              4 road kills with any air vehicle in a round

Santa's Little Helper    10 Assist Points in a round

Avenger Trophies         50 times Avenger Trophies

Savior Trophies          50 times Savior Trophies

Dead Eye Headshots       100 Headshots with any sniper rifle

Snake Eyes               In a Round get 11 Kills as two different classes

Squad Avenger Card       Get 100 Avenger Points Avenging Squad Members

Squad Wild Card          In a Round 1 Squad member trophy per Squad Member

Staying Dry              In a Round 2 seconds air time with a sea vehicle

Straight Flush           In a Round Destroy 1 vehicle of each kind

Strike                   In a Round Kill 10 Enemies at the Same Time

Tank Buster              In a Round Kill 5 Tanks

Three Of A Kind          In a Round destroy 3 vehicles of the same kind


Efficiency trophy's
     Complete  the  following  task in multi-player mode to unlock the
corresponding trophy.

Unlockable:              How to Unlock:

Assault rifle 
efficiency trophy.       Get 6 kills with an assault rifle.

Avenger trophy.          Get 3 avenger points.

Big guns trophy.         Get 5 kills with artillery.

Carbine efficiency 
trophy.                  Get 6 kills with the M16A2.

Clear skies trophy.      Get 5 kills with a stationary weapon.

Combat aviator trophy.   Get 5 kills with an air vehicle.

Demo pack 
efficiency trophy.       Get 3 kills with C4.

Explosives efficiency 
trophy.                  Get 10 kills with explosives.

Firearm's efficiency 
trophy.                  Get 3 kills with a handgun.

Frag out efficiency 
trophy.                  Get 3 kills with a grenade 
                         while playing demolitionists.

Grenade launcher 
efficiency trophy.       Get 6 kills with a grenade launcher.

Mortar strike 
efficiency trophy.       Get 3 kills with a mortar strike.

Rocket launcher 
efficiency trophy.       Get 3 kills with a rocket launcher.

Shotgun efficiency 
trophy.                  Get 5 kills with a shotgun.

Laser designating 
efficiency trophy.       Get 3 kills from laser designating.

Marksman trophy.         Get 5 kills with a sniper rifle.

Light machinegun 
efficiency trophy.       Get 6 kills with a light machinegun.

Melee combat trophy.     Get 5 melee kills.

Mine placement 
efficiency trophy.       Get 3 kills with mines.

Naval surface 
warfare trophy.          Get 5 kills with a sea vehicle.

Tank warfare 
efficiency trophy.       Get 5 kills with tanks.