How to do camera scrolling?

I would like to make a 2D scrollable map using camera scrolling, however I have no idea on how should I go about doing it. Can anyone help me with this? Thanks.

I assume your map is on the x,z plane.

float pan_speed = 10.0f;

function Awake(){
camera.y = 100; //put the camera above the world
camera.Rotate(transform.right, 90); // transform the camera on
}

function Update(){
if(Input.GetKey("up"))
  camera.Translate(Vector3.forward * Time.deltaTime * pan_speed, Space.World);
if(Input.GetKey("down"))
  camera.Translate(-Vector3.forward * Time.deltaTime * pan_speed, Space.World);

if(Input.GetKey("left"))
  camera.Translate(-Vector3.right * Time.deltaTime * pan_speed, Space.World);
if(Input.GetKey("right"))
  camera.Translate(Vector3.right * Time.deltaTime * pan_speed, Space.World);
}