Make 3rd-person character smoothly rotate with mouse camera

Heey,

I'm making a 3rd-person game, and I want the character to rotate along with the mouse I mean, if I mouse with my mouse, to a certain point, I want my character to rotate to that position aswell! Smooth enough so someone's head can't go crazy.

I'm using this for my character: (http://hastebin.com/sorufodope.cs)

 public class CharacterMovement : MonoBehaviour {
 
     public CharacterController controller;
     
     public float speed = 6.0F;
     public float jumpSpeed = 8.0F;
     public float gravity = 20.0F;
 
     private Vector3 moveDirection = Vector3.zero;
 
     void Update () {
         float v = Input.GetAxis ("Vertical");
         float h = Input.GetAxis ("Horizontal");
 
         controller = GetComponent<CharacterController> ();
 
         if (controller.isGrounded) {
             moveDirection = new Vector3 (0, Camera.main.transform.localRotation, v);
             moveDirection = transform.TransformDirection (moveDirection);
 
             moveDirection *= speed;
         }
 
         moveDirection.y -= gravity * Time.deltaTime;
         controller.Move (moveDirection * Time.deltaTime);
     }
 }

What's next?

Thanks in advance, Pr0totype2