1. General: Contractor Associations - see here. Contractor association websites provide a wealth of roofing resources, including lists of their members. Most contractor associations have professional ethics requirements for their members, which makes them a pretty good place to start if you're looking for a contractor. Members tend to be larger roofing companies who are more typically focused on commercial roofing, so they may not always be the best place to find a roofer for smaller residential jobs.
5. Licensing: To verify a roofing contractor's license, and to find out the roofing contractor licensing requirements in your state, see Roofing Contractor Licensing and License Verification.
6. Solar Energy: Find a rooftop solar installation contractor or designer at the Rooftop Solar Resource website, which is “a comprehensive resource for homeowners and business owners, building managers and consumers looking for information regarding solar rooftops…"