SOCOM U.S. Navy Seals Cheat Codes

Secret Headset Commands
"Bravo open/close door" (when close to a door -- point at it with the crosshairs)
"Hands up, get down" (sneak up to guards and yell it)
"Bravo, diffuse bomb" (when pointing crosshairs at bomb)
"Team, low profile" (team sneaks around killing terrorists stealthy)

More Weapons
After beating SOCOM for the first time you will then have access to all the weapons in the game in single-player mode.