Finds a child by name and returns it.
If no child with name can be found, null is returned.
If name contains a '/' character it will traverse the hierarchy like a path name.
// The magical rotating finger
function Update() {
aFinger = transform.Find("LeftShoulder/Arm/Hand/Finger");
aFinger.Rotate(Time.deltaTime*20, 0, 0);
}