Sounds like you are dealing with what I dealt with... we trained our 2 year old son in about 2 days. He did great during the day having very few accidents. For naps and at night we put on a pull up. After a month, he did not have any accidents during his naps. So, I took that away (and put on underpants during naps). After about 2-3 months I noticed he was dry during the night too, but I STILL kept a pull up on him during the night (to save the sheets and to save me from waking up to change the sheets in the middle of the night). He does wake up by himself about once a night to go to the bathroom. Since he's still in his crib I have to get up to put him on the potty. I don't mind this considering he wakes up dry. I figure that once he's in a big boy bed he'll be able to get up on his own to go.
Note: In the very beginning, our son would have dry diapers at night, but then he'd go a week or two with wet ones. (It was frustrating to see the inconsistency.) By about a month or two he began waking up to go and had very few wet ones by two months after day training.
I have seen kids as old as 4-5 who still wear pull ups, but I know many kids who wean off of them within a couple months.
Also, I do limit drinks close to his bedtime. I've also noticed that when I do allow him to have juice (or something other than milk), he has to go more often at night. So, I try to avoid those types of drinks in the evenings.