All kids are different but I can tell you the easiest way to potty train him at this age is to get rid of the diapers (and pullups!), stick him in normal boy's underwear and be prepared to start cleaning up messes.
Following these steps should make it a bit easier.
1) Explain to him about the potty and that all kids by the age of three need to use the real potty and not baby diapers. Stress the whole big boy thing and associate diapers with being a crying baby
2) take him to the store and let him pick out a potty, even if you already have one. Letting him do it will give him control, also let him pick out several pairs of real underwear.
3) explain again and ask him questions about going to potty (what does it feel like when you have to go pee? type questions). It helps if you have a doll that wets so you can show him in his own potty what he's to do. I always would say things like, "Oh I wish I had a potty I didn't have to share with everyone else like you do."
4) throw out all diapers/pullups, anything for babies because he's a 'big boy'.
5) take him to the bathroom every 15 minutes or so the first day, every 30 minutes or so the next, 1 hour the next.. gradually work it down to just asking him every hour if he needs to use the potty. Don't use diapers in the night or pullups either. Just get a lined bedsheet for his bed. It sounds cruel the the more often he wets himself and sees how gross it feels, the quicker he'll be trained.
6) Give him a treat every time he goes to potty like a big boy. My kids were crazy about gum and since it was only something big kids could have, they knew they were acting really grown up when they used their potty.
7) let him plan something for when he goes for a couple days without an 'accident'. Like going to the park or whatever. Plan something big for when he goes for a couple weeks without an accident. Like a party with a couple friends or he gets a bike or something. You know what he's wanting the most. Let him know about the special reward for being completely potty trained.
When he has accidents, just explain to him again what it is he's supposed to do. Never get angry at him over it, even if it seems it's deliberate. Make him help you clean it up even if it's just putting his wet underwear in the washing machine. You have to make wetting himself as unpleasant as possible without putting fear into him.
Using this method, my 1st child took 3 days to potty train him. I used the pullups with my 2nd son and he ended up being a bedwetter for several years. My third one took a little longer but I made the mistake of using pullups when we'd go out anywhere because I didn't want him wetting in public or in his car seat. I've used it potty training kids I've baby sat and generally within a few days, they're trained. I make a big production out of how grown up they're getting when they use the potty and just kind of frown and get them to help me clean up the mess and say things like, "Well there's always next time to make it to the potty." Kids love to please adults but like I said, You don't want to scare them so a little disappointment is effective.
Just be prepared to clean up lots of messes for the first couple of days and don't stress over it. He's not going to grow up and be a 35 year old man, still wearing Pampers.
Best of luck to you both.