Georgia custody law

First and foremost - if there is not a clause in your parenting plan about move aways and what either of you have to do as far as permissions and timeframe - you need to talk to your attorney and get a modfication put in before your finalization if at all possible.

What she can or can't do depends on what the custody agreement is - if she has sole custody, she can pretty much do what she wants & you have no recourse. If you share custody, especially legal custody, if she leaves with the children out of state without your consent or knowledge, that is pretty much parental kidnapping & you and your attorney can decide if you want to get the police involved, or just take it to court to force her return and possibly remand custody to you.

Now if she does tell you she is going, then it is up to you to file in court to force her to stay.

i don't believe any parent can leave the state without the other parents permission (during/after the divorce). before the paperwork starts, either parent can pretty much do wahtever they want. 

read this:
http://www.divorce360.com/child-custody-and-visitation-360.aspx