Tire rotation and tire balancing is more or less separate issues. You really only need to balance the tires when you are installing a new tire on the rim. It usually does not require rebalancing even if you rotate the tires. But, if you start to feel some vibration on the vehicle through the steering wheel when traveling at certain speed on the highway, then you will need to have your tires balance checked. It usually means that a wheel weight has fell off. So, it is always a good idea to test the vehicle on the highway( above 70 MPH ) to verify the tires are installed correctly( means no vibrations ).
About tire rotation, I agree with article aNoodle provided.