We were the same with out little girl (10 months), where we would bring her into our bed anywhere from 3am- 5am. We did this as she had silent reflux and was on medication from 6 weeks old. You could often see the pain on her face with it, and she took a lot of comfort from being with us. That has now passed, but the coming into our bed hadn't, so a week or so ago, we tried controlled crying. Short story, it worked. It's hard for a few days/week, but once you are passed that, it's plain sailing.
She is now sleeping from 7:30pm until between 5-6am. She used to wake up at least once a night, and was often in our bed from about 3:30/4 as she wouldn't settle back in her own bed.
Now we put her to bed awake and she just goes to sleep on her own. If she wakes in the night, she knows we wont come, so just goes back to sleep. Occasionally we hear a wimper for a few secs, then she is zonked again. She also now sleeps longer. She still comes in our bed if she wakes after 5, as that is her usual getting up time, but lately she has been waking closer to 6 and we get up not long after 6 anyway, so just bring her in our room.
I have read that it doesn't work for everyone, but it is worth a try. It is very hard at first to hear them crying, but just remember, they aren't in pain, they are fine, and try to have something to distract you.
Oh and read up on the different techniques. It's not just a case of leaving them in there crying and that is it.
Hope that helps.