Basically he is in a bad routine of getting your attention this way. I had to go through something similar - and it took three nearly sleepless nights.
I created a very regular routine. Bathtime and bedtime at a certain time of night, tuck her in, hug, kiss, say goodnight and close the door. When she cried for me I waited longer and longer periods of time before I went in to check on her. The first time I checked, I reminded her "it's time to go to sleep. I will see you in the morning, goodnight" leave the room. Each time I said less and less until I just went in there, put her back in her bed and left without saying a word. Eventually she wore herself out getting in and out of bed. Three nights later it was over - she was staying in bed without problems.
I found the routine of bathtime, bedtime, and even morningtime (same time each day) was a tremendous help in getting her settled.
at 11:30 PM on Sep. 15, 2009