ok so this code almost works. attach this code to your main camera. make a sphere. put that sphere in this scripts transform slot.
make a plane extending forever.
press play.
notice how the sphere goes where its supposed to (aka the hit.point of the ray) and then zooms towards the camera.
odd.
var aimTarget: Transform;
var hit : RaycastHit;
var point : Vector3;
function Update () {
var ray: Ray = Camera.main.ScreenPointToRay(Input.mousePosition);
if (Physics.Raycast(ray, hit)) {
aimTarget.position = hit.point;
print(hit.point);
}
}