My daughter started training at 18 months. 50% of the world's babies are trained by 12 months...think 3rd world countries where there is limited availability to diapers and where moms wear their babies. You can read all about it in a NY Times article (October 2005).
http://www.nytimes.com/2005/10/09/nyregion/09diapers.html...
The article states that we actually train kids in the first 12 months to ignore the signals they get telling them they need to go. It means tuning in to the individual baby's rhythms and signals.
My daughter was not fully trained until she was 2-3/4 years, but we saved a lot on diapers that were not soiled. I'd put her on the toilet as I was getting in the shower in the morning and by the time I'd gotten out she'd be done. She'd sit there happily 'reading' a book. We kept a stack of books and a little step (for me to sit on those times when I wasn't showering) in the bathroom and she got to choose the book. Sometimes it means changing the rewards to whatever the child wants most.
Daycare worked with me. They'd put her on the toilet at the regularly scheduled diaper change, change the rest of the kids, take her off and put her diaper on. Sometimes she'd be successful, sometimes not. Seeing her doing it encouraged some of the other kids to try it and they probably trained earlier than they might have otherwise.
We still put pull-ups on her at night. Sometimes she wakes up dry, sometimes not.
Good luck, most of all, relax. If you're tense about it your son will sense it and will be, too. Then he'll lose interest.