Lucky you! I've known a few kids who essentially self-train that early, and have heard about many others on mamasource. Your son sounds pretty mature and self-directed. Follow his lead, and it could work. Ask him questions, offer him help and encouragement. Ask him to tell you when he needs to go, so you can help him clean up after. Get him some big-boy pants and teach him how to pull them down and up. Make a game of trips to the potty, and celebrate whenever he succeeds (but material rewards are not needed). If he has accidents, handle it calmly, and assure him he'll do better next time.
Be prepared for some backsliding, though. Sometimes early trainers eventually become overwhelmed by the ongoing obligation of getting to the potty on time, every time. That's okay, too. Going back to diapers for awhile makes a good case for being trained, and kids will decide to go back to the undies when they're ready.
If he wakes up dry, then he's probably going to be trained for day and night. If he still wakes up wet, let him stay in overnight diapers until his bladder and nervous system catch up with his ambitions.