Fallout: Brotherhood of Steel Cheats

Unlock characters
To unlock characters complete the following:

Unlock Patty = Beat the first chapter.
Unlock Rhombus = Beat the second chapter.
Unlock Vault Dweller = Beat the game.

Unlock videos and pin-ups
To unlock a level's cut-scenes, simply complete the chapter. Once you fully complete the game, you can access pin-up photos, and tons of concept art in the Bonus option of the main screen.

Defeating the Raider Commander
Use an incendiary cannon, two barrel shotgun, sledge hammer, and 35 stimpacks.
Note: This was done with a level 9 Cain under the normal difficulty setting.

Hidden Weapons
Slugger - In Los, locate the docks and the alley behind the last of the sludge pools. On the other side of the fences is a group of ghouls--nail 'em with grenades, and as you exit the alley you'll encounter a larger ghoul. Take him down and you'll be rewarded with the Slugger bat.

Meat Cannon - Again in Los, pay a visit to the Bridge chapter. Near the console where you save your game, you'll need to hop over the dark abyss to reach an island on the other side. In the lockers of the truck that's on the island you'll find the Meat Cannon.

Ultimate Weapon - In Los, on the Eastern Bridge, you'll meet a Ghoul VT engineer. He tells you that any junk you may find can be brought back to him and he'll try to make something out of it for you. As you adventure through Los you'll begin to find junk. DO NOT return the junk to the engineer until you have FOUR separate pieces. When you give four pieces of junk to the engineer he will make a Super Sledge for you (80-100 points of damage). This melee weapon is the very best in the game up to this point. Fewer pieces of junk given to the engineer will result in him creating less-exciting and less-powerful items.