Hi, I can only speak from my experience of potty training my 2.7 yr old DS this week. I decided to take a week off work to really focus on it, but had been leaving the potty out/encouraging use of the potty for a couple of months beforehand. I also showed him the 'big boy pants' that I'd bought him so that he would get excited about wearing pirate pants or whatever (got mine from John Lewis - bought 3 packs of five!). I also made sure that I explained a few times to DS ahead of potty training week that we would not be having nappies any more in the day time, so that it didn't come as a shock.
The other key factor was working out a rewards system. My DS likes stickers and choc buttons so that's what I decided to do. So last Monday morning, I took off his nappy in the morning and said he would be wearing his big boy pants. However, with it being quite mild, I decided to whip them off and he was naked from the waist down (apart from socks!). This seemed to work much better as he didn't have the 'safety net' of pants if he wanted a wee. I would regularly ask him if he needed a wee, or use a motivation i.e. 'We won't go out for a walk until you've had a wee'. This worked well. He also quite enjoyed having 'nature wees' while we were out in the park, along the canal etc.. I had a friend round on day one whose little boy is potty trained and when my DS saw him weeing straight into the toilet, he said 'I want to do it like that'! So we've had wees in the potty and on the toilet ever since. Of course, we've had a few accidents, mainly after he's woken up from nap time (and usually has an erection bless him!), but I've resisted using pull-ups as I feel they send out a confusing message. He just has a normal Pampers nappy for night time (and I explained to him at bathtime that he would have a nappy for bedtime).
Poos have been a slightly different experience. My DS likes privacy when he's having a poo so he will tell me to leave the room. Trouble is, the first one he did was while we were in the garden, so it was too late to get the potty. Second one was done half in his pants (solid, thankfully!) and half in the potty. However, he has a present all wrapped up and stashed high up on a shelf where he can see it, and I've told him that when he does a poo in the potty, he will get the present.
I think he's totally got the wee thing now (we were in the middle of Toys R Us and he twice told me he needed the toilet, so I told him to hold it and we legged it to the loos) but we need to do more work on the poo side of things.
The other thing you'll need to think about is can your DS pull his own pants down? I've had to teach my DS to do that and I know some people buy the next size up in pants so that they are easier to take down.