B.M.
I potty trained when my son was 2 1/2. I just decided that we weren't going to do diapers at all and I went straight to underpants. A pull up is just a glorified diaper if you really think about it. It truly doesn't teach them much except that they can pull it up and down. Yes I had a lot of accidents and some cleaning but in the end it was well worth it. We had him in underpants through the night about a week after I started.
Good Luck
B.