Is there such a thing? How does it work?

DD is six months and can sleep through the night, but doesn't. She goes to bed in her crib around 9 pm, wakes two or three times at night to nurse, hangs out in our bed using me as a pacifier, and now has a new thing - she starts kicking me and screaming around 5 am and can go on like this for an hour or two till it's time to get up. I get it, she's teething and just got over a cold... but I don't think she's developing good habits, and judging by the screaming, cosleeping isn't comforting her much any more.

I think it's time for sleep training, except we live in a small apartment, and if she screams in the middle of the night she will keep everyone awake. Suggestions?