Aw, how wonderful of you! Since he's so tame, I would definitely take him to the vet for a check-up (make sure you're not bringing any parasites into your home), and ask them to scan for a microchip.

I would also potentially post on craigslist, and put some posters up around the neighborhood, just in case someone's looking for him. And if it turns out he's already been neutered, you can be almost positive someone's looking for him. It can be VERY hard to find their homes, and reuniting kitties with their families is rare. But I'd want to make sure someone's not missing him.

But what a handsome guy!
