My older son trained shortly before he turned three -- and about two weeks after his younger brother was born. Once he saw the baby wearing diapers he was ready to be done. At 5yo, though, he is still not night trained. He stays dry because we take him to the bathroom while asleep in the middle of the night, but he never, ever wakes up on his own.
My younger son, now 2.5, trained immediately after he turned two. I did almost nothing; it was all about wanting to be like his big brother. He also stays dry at night and regularly wakes up when he has to go. (I keep him in pullups, though, because his older brother has to wear them and I just can't open that can of worms.)
FWIW, I know lots of folks have great success with the run-around-pantless thing, but it completely freaked my older son out. He did MUCH better with the security of pullups. #2, OTOH, was happy as a clam to run around sans pants.