How can I make the Transform.LookAt function look smoothly at a target?

I've tried looking around for a few answers and I found several discussions but I seem to be having a problem making my Transform.LookAt function look smoothly at a target. I'm doing something quite wrong but I'm not sure what it is

Heres a snippet:

var target : Transform;
var oldLookAt : Transform;
var lookAtTarget : Transform;
var pointA = oldLookAt.transform.position;
var pointB = lookAtTarget.transform.position;
var smoothLookAt = Vector3.Lerp(pointA, pointB, Time.time);

function Update () {
// Early out if we don't have a target
if (!target)
    return;
transform.LookAt (smoothLookAt);
}

I used point a and b because The lerp function doesn't take Transforms so I made them into Vector3's or at least I think I did. At this point it just snaps to what I think is the global origin. What I wanted is for it to smoothly Glide look over to my new target.

What could be my problem?

Check out the standard assets: Camera Scripts > SmoothLookAt