Start with these guys, they will be the most helpful and knowledgeable!
(in no specific order)
malignity
Michigander
venator
Bronson
DrTodd
Also make sure you put up the legal disclaimers, stuff like "I Am NOT A Lawyer!", and maybe "I do not recommend Open Carrying, unless you have researched the issue yourself, this app is a reference tool only, and is not legal advice.".
I am not saying to charge for it, but maybe a free version (a lite version), and a full paid version, something with GOOD separated categories, a good user interface. I would pay for something quality! For sure!
Good luck! Hope to see it soon!
God Bless!
Peace be with you and your piece!