Are possibly PCSing overseas or is she deploying? If you are going together to a place like Germany or Japan then that is a PCS. If just she is going with her unit then it is a deployment.
For either you will should have several copies of your birth certificates (yours, your spouse & childrens), marriage certificate, SSN cards.
You should also get POA - Power of Attorneys that can be done through JAG on base. For things like moving into Housing (both military and PPV), filing for putting things into or take out of storage, to ship a vehicle overseas, to buy a car, to replace a missing ID card, getting a passport for the children, leaving the country with the children....
Make sure you ID card will not expire while she is deployed
Have copies of all medical records and dental records at home
Have Tourist Passports for all of you and make a copy of the #'s