J.W.
I wish I had gotten on a schedule earlier than I did. I waited until my twins were 6 months old and I had had it and was ready to let them cry. We put them on the schedule that is detailed in "Healthy Sleep Habits, Happy Child" by Marc Weissbluth. Basically it outlines different schedules for different ages, but the end result (as early as 3-4 months) is sleeping 12 hour nights. I never thought I could get them on the schedule. It took a really hard week, but once they got used to it they THRIVED.
Two of Weissbluth's main ideas are: never keep a baby awake for longer than a 3-hour stretch and sleep begets sleep. Our current schedule since 1 year: 6:30am up, breakfast at 7:30, play, nap 9-11am. Lunch at 11:30, followed by a nap beginning 3 hours from when they woke up from the morning napp (between 1:30 and 2pm). Once they wake up, play, dinner at 4:30, bath at 5, bed at 6pm. We rarely hear from them until 6:30am (minus them being sick, having shots, teething, etc :) ). I'd check out that book if you are interested - it's popular in my twin group. Best of luck. Schedules are great!