How do I stop my character from rotation relative to the frame rate?

In my game i have my character facing a wall. Behind it though, there is a high poly city. Depending on the frame rate, the character rotates slower or faster depending on the frame rate. Here is my script.

function Update ()
{
      {
        var controller : CharacterController = GetComponent(CharacterController);

        transform.Rotate(0, Input.GetAxis ("Horizontal") * rotateSpeed, 0);

        var forward = transform.TransformDirection(Vector3.forward);
        var curSpeed = speed * Input.GetAxis ("Vertical");

        controller.SimpleMove(forward * curSpeed);

      }

}

Thanks for your help.

I guess you could use a DeltaTime instead, but games are very much frame dependent; that's sorts what it's all about. I'd look at lowering draw calls, use culling layers and reduce poly count.

transform.Rotate(0, 5*Time.deltaTime, 0);

And some possible answers / pointers in this thread. http://forum.unity3d.com/viewtopic.php?p=260461