Can a noncustodial parent legally move out of state without permission from the court?

I live in the state of Georgia. My husband and I have wanted to get custody of my stepson for quite some time, but we were waiting for the right time out of fear of losing. His mother is very fickle about relationships, where she lives, jobs, etc. She has him around instate about 9 times ( in and out of boyfriends and family member's houses) in the 26 months that my husband and I have been married. Now we found out that a few weeks ago she moved him out of state (about 4 hrs away) without even telling us, let alone getting permission from the court. Oh and I forgot to mention that originally, we lived about 1 1/2 hrs. away, but moved 6 mnths ago to be closer to him. but back to the question at hand, Can she legally move him out of state without permission?