Starting July 1, 2009 all contractors must be registered with the Pennsylvania Attorney General's Bureau of Consumer Protection (PA Senate Bill No. 100) and must show their registration number on all forms of advertising. What this means for you the customer , "fly by night contractors"  will no longer be able to operate under legitimate guidelines. You must now have a contract listing work to be performed, materials to be used, specifications...unchangeable without a written change order and the total price due under the contract .The contractor must have a registration number and show proof of insurance!