Rotating A Character 180 Degress

So, I'm working on a 2D platformer. But, I'm editing the FPSWalker script to fit my needs. I want the character to rotate 180 degrees on the Y-Axis depending on which direction he's moving. How could I do this? I know that their's transform.rotate, but my brain is trying to comprehend..

  var playerSpeed = 15.0;
var jumpSpeed = 15.0;
var gravity = 20.0;

var AntiBunnyHop = 1;

private var moveDirection = Vector3.zero;
private var grounded : boolean = false;
private var jumpTimer : int;

function Start () {
    jumpTimer = AntiBunnyHop;
}

function Update () {
    if (Input.GetButton("Attack")) {
        BroadcastMessage("Fire");
    }
    if (Input.GetButton("Attack 2")) {
        BroadcastMessage("Fire2");
    }
    transform.position.z = 0;
}

function FixedUpdate () {
    if (grounded) {
        //Haha, your on the ground you loser.
        moveDirection = new Vector3(Input.GetAxis("Horizontal"), 0 , 0);
        moveDirection = transform.TransformDirection(moveDirection);
        moveDirection *= playerSpeed;

        if (!Input.GetButton("Jump"))
            jumpTimer++;
        else if (jumpTimer >= AntiBunnyHop) {
            moveDirection.y = jumpSpeed;
            jumpTimer = 0;
        }
    }

// Apply gravity
    moveDirection.y -= gravity * Time.deltaTime;

    // Move the controller
    var controller : CharacterController = GetComponent(CharacterController);
    var flags = controller.Move(moveDirection * Time.deltaTime);
    grounded = (flags & CollisionFlags.CollidedBelow) != 0;
}

@script RequireComponent(CharacterController)

Use this:

function Update () {
    if (Input.GetButtonDown("Fire1")) {
        transform.eulerAngles = Vector3(0,180,0);
    }
}

to turn your character around.