I was pretty lucky with DD she was dry by night at 2, I was really shocked, but it was ehr chocie, she kicked off about nappies one day and never wore them again.
DS wasn't quite so easy, he was three in dec, put him in pants about 6 months ago, didnt do potties with either of them, they just carry them around and you get wee everywhere. I'd wait til it's a bit warmer then prime him, tell him 'Soon be time for no more nappies, so you'll need to tell mummy when your winky tinkles and go to the toilet'.
Then just go cold turkey, I think DS wet his pants about two/three times a day for about 3/4 weeks, then he just clicked.
He's not good at holding it still though, he'll say suddenly, in a shop, 'Mummy I need a wee' then he wees about 2 minutes later, so be prepared for mad dashes, and toilet breaks when out, always make him wee before you go out, and try to keep spare pants/trousers in your bag just incase.