Shoot a man in the same spot until you have no more ammo.  The, use you PP7 to shoot his gun once, then grab it.  Shoot Q and Monnypenny who should be walking around to get the old bond.

Unlock the Golden Gun in Multi-Player

Beat the Precious Cargo level with all 007 icons, and a rank of Platinum.

Unlock the Golden Gun in Single Player

Beat the Trouble in Paradise Level with a rank of Gold.

Golden Accuracy Power-up

Beat the Bad Diplomacy level with a rank of Gold.

Unlock the Golden CH-6

Beat the Precious Cargo level with a rank of Gold.

Unlock Unlimited Ammo for the Golden Gun

Beat the Evil Summit level with a rank of Gold.

Golden Armor Power-Up

Beat the Forbidden Depths level with a rank of Gold.

Golden Bullet Power-Up

Beat the Poseidon level with a rank of Gold.

Golden Grenade Power-Up

Beat the Night of the Jackal level with a rank of Gold.

Golden Clip Upgrade

Beat the Cold Reception level with a rank of Gold.

Unlimited Car Missiles

Beat the Dangerous Pursuit level with a rank of Gold.

Unlock the Lotus Esprit Car

Beat the Streets of Bucharest level with a rank of Gold.

Unlock Viper Gun for Multi-Player

Beat the Night of the Jackal level with all 007 icons, and a rank of Platinum.