My son refused to wear the training pants, too. He was about 2 1/2 when I first tried. We were about to move and then my husband was going to deploy, and he wasn't getting the hang of potty training so I gave it up (they say it's never good to have huge changes when potty training- I was just hoping to have it done before all of the changes happened). A few months later (he was 2 yr 9 mo), when things were more settled, I decided it was time and put him in underwear (the real stuff - no training pants). I talked about it a couple of days in advance and told him the exciting news that he was going to wear big boy underwear from now on. We have some fun designs that he loves - cars and trains and such, as well as some plain white ones just like Daddy's - and I let him pick which ones he wants to wear each day (I don't give him a whole lot of choices throughout the day, otherwise everything becomes a battle, and since potty training can be such a power struggle with many kids, I felt he should be able to choose his underwear, especially if he is mature enough to use the toilet, then he is mature enough for that freedom - and he loves making his choice! Sorry if that is TMI!!) Anyway, we stayed home for a couple of days and he did great - not one accident. I got him some mini cookies that he loved and he got two cookies each time he used the toilet to stay dry and clean. Since things were going so well, we went out to dinner the second night and he had an accident while we were out, but that is the first and only accident he has had! He did not like being wet and I think it only happened because he was in an unfamiliar environment and he was not used to controlling his bladder in strange environments. After a couple of weeks, we went from cookie treats to a sticker chart and a special reward when he filled up his chart. After a couple of months, we no longer needed that. It's now been about 6 months and I feel the diaper days are only a faded memory for him (he nighttime trained just a few months after the daytime training). We always tried to be very low key about the whole thing, especially when there was an accident (he only had the one accident during the day and he had two nighttime accidents early on in that process). But we always made a BIG deal when he used the toilet to stay dry and clean - major fanfare, and we still praise him often for that success and for being such a big boy.
He is my only experience, so I don't know if what worked with him will work with another kid. Every kid is different. His little brother is about to turn two so I am watching in great anticipation (and a little fear) for signs that he is ready. And I hope for the same "easy" experience, but expect it will be very different.
I hope the success with your son comes soon - it would be so nice if he were trained before the new baby arrives (then expect him to regress - I hear they always do when a new baby arrives!).