My perspective is that kids potty train themselves, parents have little if any control over it. That said, there is typically a window right around 18 mos where a child will show interest in the potty. If you encourage, support and take the time to respond to the "training" you may be lucky and have the child trained at two (I did this twice). If you miss the window, the opportunity doesn't usually present itself again until three - three and a half. If you miss this window (I did once) between two and three, all you can do is find a rewards system that works and keep at it, making sure not to try to push or force the isssue. Some rewards may be: m&ms, marshmallows, stickers, sticker calendar for big prize, talking about giving a "potty party" with charachter cake and balloons when child is fully trained. Other than that, my opinion is that you will be beating your head against the wall.
You can try "big boy" underwear, but even his wetting those is no guarantee that he won't just keep doing it...which creates quite a constant mess. There is the hourly alarm which will train YOU to take him to the potty. There is letting him run around naked, which some people swear by, but got my carpet peed on more than once.
Anyway, I hope there is a method here that works for you, just be supportive and laid back and he will decide when he is ready.