Unlimited health:
     At  the  PDA  factions  screen,  press  Up, Down, Up, Down, Left,
Right, Left, Right

Unlimited ammunition:
     At  the  PDA  factions  screen,  press Right, Left, Right, Right,
Left, Right, Left, Left.

Full fuel:
     At  the  PDA factions screen, press Right, Down, Left, Up, Right,
Down, Left, Up.

$1 million:
     At  the  PDA  factions  screen,  press Right, Down, Left, Up, Up,
Left, Down, Right.

All factions neutral:
     At  the  PDA  factions  screen, press Up, Up, Up, Up, Down, Down,
Right, Left.