Usually as long as both institutions are under the same accrediting body, the credits should transfer back and forth. Most public schools are accredited under North Central so it should be easy to transfer credit from one school to another. You can run into difficulty if one is regionally accredited and the other is nationally accredited. I would advise you to find out if the school you are currently attending and the one you are thinking about attending are both regionally accredited. If they both have the same accreditation, then it will be up to the school that you want to transfer to inform you which credits they will accept. I would suggest you find out this information Before you transfer. If some of your credits do not transfer straight across, then ask if perhaps you can CLEP out of some of the coursed you already took.
Best of luck.