Had the same problem. My firstborn is what I call a "high needs" kid. Even in the hospital, he wouldn't sleep in the bassinet, only next to me. In the first 48 hours, I got maybe 2 hours sleep because I kept trying to lay him down in his bassinet. I gave up and became a co-sleeper (and got WAY better sleep--next to me, he would sleep for 6 hour stretches, even that first week). He's two now and although he's got his own bed, I STILL cuddle him to sleep! I co-slept til he was about 18 months (since I'm a working mom, I didn't mind--it was my chance to catching up on cuddling).
You've probably heard about the "bedtime ritual?" they do help to settle them down. Bath, bottle of water (helped for weaning), lullibies, cuddling,--repeat each and every fricken night-- and he'd be off to dreamland. One positive about co-sleeping--there is good news for the future! Since he wasn't too attached to his crib and was used to beds, I found it EXTREMELY easy to transition him to a big boy bed! I just cuddle him to sleep in his own twin bed (piled with his favorite stuffies), then quietly slip out after he falls asleep (in about 10 to 15 minutes, sometimes as long as 25 if he is restless--again i don't mind too much, I try to think of it as our special time, esp now that he has a new baby brother).
As for my newborn??? That BLESSED WONDERFUL ANGEL has no problem going to sleep on his own. I can't wait til he sleeps through the night. And unlike his brother, no colic either. He's my easy kid! I still co-sleep with him, but mainly becasue I am too lazy to get out of bed to feed him :)