That's a good question - and it has a good answer.
The Naturist Societ has a webpage with the state laws and also pending and recent legislation.
Check it at:
http://www.nac.oshkosh.net/StatesProvincesTerritories/states.html
They have an outside service that monitors all state legislatures for new bills that would affect our interests so it's a great organization - this is actually under the Naturist Action Committee - a branch of the Naturist Society.
dick