The HSUS offers database of U.S. and Canada TNR groups and programs
Even if you're doing most of the TNR work yourself, it can be helpful to contact an experienced group in your area. They may be able to point you to spay/neuter resources, trap banks, volunteer help or more.
The Humane Society of the United States has compiled a comprehensive list of agencies in the United States and Canada which work with community (feral and stray) cats, including community cat groups, shelters, rescue groups, spay/neuter clinics and veterinary clinics. Enter your state, territory or province and a list will appear of groups, their locations and contact info. Be sure to take advantage of this great resource!