Wow - you're getting a lot of answers that will either take forever or may drive that cat away. That is a hazard of this list - anyone can respond, but not many people have actual experience.
Your local animal shelter or Humane Society should loan you a Hav-A-Heart trap. If not, Lowes and Home depot carry them. This is a humane trap that will frighten him but not hurt him. Bait it with whatever you give him that he likes to eat. Monitor it closely, so that he isn't in it for long. Set it up when you are home and where you can easily see it without frightening the cat away. Unset the trap when you go to bed or out for the day and reset it when you get home.
Be aware you may accidentally pick up an opossum or other wild animal ( or the neighbor's cat), in which case you just release it, no big deal, and try again.
Once you get him inside, take him to a small room ( I recommend a bathroom in case he sprays so you can easily clean it) and release him. Have it prepared with a litter box and food and a place he can go to hide and sleep.
Most people will recommend that you leave him alone to get used to his surroundings. I work with ferals and strongly disagree with this. He will be very vulnerable at this point, and will be more likely to let you handle him than once his confidence is back. Sit with him, talk to him, and hand him cat treats. Pet him as much as he allows without scratching or biting you. Most feral cats will hiss and cringe, but will pet you pet them. I pick them up and put them on their rump on my lap ( like a baby) if they let me. They will curl up in a ball, but hug them and they often start purring, if not that session then the next. I basically do occupational therapy like an OT would do with an autistic child with my ferals. You work with what they like best and what scares them at the same time an they open up. But always do it in a safe, small room. If you are curious about OT, look up Sensory Integration and proporeception ( which is what a hug gives us, and which soothes our neurological system, whether we are cat or human). Figure out what sort of touch he likes best ( ferals usually seem to prefer a firm reassuring touch) and offer that constantly.
Visit the room often - several times a day, until the cat feels comfortable, and then give them more and more room to explore, but not the whole house at once. Always offer a hiding place, but one you can reach into if you need to get the cat out. Don't let every Tom Dick and Harry invade that space, because then it won't feel safe, but he will soon trust you to do it.
Years of experience working with 'scratch and dent' cats.