There are two simple ways to, in effect, keep you money as you disband:
1. Spend the dollars down to zero before you finally, formally disband. In this way the moeny is all spent the way you want, where you want (at your school most likely, on great things like field trips, teacher support, supplies, speakers, involvement events, playground, etc.).
2. Form your new 501c3 PTO before you formally disband your PTA. Once the new PTO is up and running, the disbanding PTA could send its remaining funds to the 501c3 PTO.
I recommend the first option, as it's the one that least causes the PTA folks agita. But whatever way you go, there's no way you should lose a dime.
Your Bylaws should list the instructions in the article on the basic policies, usually the last item. Contact your local PTA council or State Office for further instructions.
Remember your Council and/or State will want to talk you and your membership. It may be that you need assistance or mediation, let them help you before you disband. This must be the vote of your membership, not just some members of your Executive Board.
Also remember that you can not keep your money, the IRS rules state that the remaining funds of the group must be given to another 501.(C)(3).
Our PTA group is trying to disband but we have had some major road blocks. Does the PTO put out any information to help us do this? Main problems are insurance and exhisting funds.