DD went through (well, six or seven hours) at a couple of months. Then at six months, she was waking every couple of hours, but by a year was sleeping through the night, mostly. I think.
DS is 10 months and has slept for 6 hours once. What a great night that was. It was the exception that proved the rule, though. He generally wakes up every 2-3 hours. I am going slowly insane.
Heremeroar - same here. DS will sometimes do four hours, but it's generally 7:30 until 11.30 and I'm working/doing housework/actually spending some time with DH...Or I'm on MN 