Sleep training is the hardest thing I ever had to do (next to the first day at preschool!!!) Maybe try doing it in stages, Super Nanny style....
first few nights, just a short cuddle
next few nights, just a back rub from the standing position
next few nights, sit down next to the crib
next few, closer to the door
next few, in the hallway
then hopefully no more..
Remember though, once you start, you CANNOT go back to your old ways. Consistency is KEY! If the child believes that you will come if he keeps crying, then he will keep crying. Children learn what we teach them, (ie. if I cry long enough, she will come and hold me), even if we do not intend to teach the lesson we did!
This scenario is ideal though and no one kid will do it perfectly. Every child is different so don't believe that there is a one size fits all approach. I did it when my kids were closer to a year, though I regretted waiting so long. I had to wait with my second though because he had digestive issues. And don't beat yourself up if the next morning you find that he was crying because of a dirty diaper. It happens to all of us!
And if you haven't started teaching him a couple of sign language signs (like for eating, drinking and dirty diaper -the three most useful in my opinion), I highly recommend it. They will help both of you when you struggle to communicate, not just at night but all the time! Good luck!