check out the Ferber book, has lots of info on sleep problems and how to get your baby to sleep. (or any age child) he recomends doing it slowly as opposed to just letting them cry it out all night.
I think it is: how to solve your child's sleep problems"
He grew out of it! He's been getting to sleep on his own for over a month now... it's great! We just pop him in the crib, he moans for a few minutes, and then he's out! Soooo nice.
We did end up letting him cry it out a bit in the middle of the night, and he only had to do it for two nights, then he realized we definitely weren't coming and since then has been sleeping through till at least 5:30 or so.