As an infant 0-6 months was your LO a good sleeper?
Not really. For the first two months or so, he'd wake up about every 2-3 hours. From about two months to 6 months he finally started sleeping a bit more, but I'd say we averaged at least two to three times waking up during the night. Oh yeah, we also co-slept together until about 4 1/2 months when he started to sleep in his crib.

If not, when did they get "better" (I don't necessarily mean sleeping thru the night, I mean just sleeping 4-5 hours at once)?
He didn't fully start sleeping 4-5 hours at once until he was about 6 1/2 months old, I think.

At what age did your LO start sleeping through the night?
If I'm remembering right, about 11 months I think. Somewhere around there, anyway. It's been so long I can't really remember!