I asked for advice a few months back about how to get my son, who is now one, to sleep through the night, and after a few painful weeks we have done it!!!  Here's my advice to other very tired mommies:

First, as hard as it is, DO NOT

rock or hold your baby until he or she falls asleep.  This gets the baby accustomed to being "put to sleep". As children get older they get used to you putting them to sleep and they will need to relearn how to put themselves to sleep.  I give my son a bottle (now a cup) of milk at bedtime and when he is done, I wrap him in his blanket, put him in his crib, turn on his bluebird music box, tell him goodnight and walk away.  The first night he cried for about 30 minutes, the next night about 20 minutes and on the third night he didn't cry at all.  Music or white noise is very soothing to a baby and helps them  relax enought to fall asleep.  We have been doing this for about 3 months and it's working beautifully. ( and if you read my question I posted a few weeks ago, you would understand why I'm so excited this is working).

Secondly, getting baby to STAY asleep.  When babies are about 4 months old, they should be sleeping pretty much through the night.  Mine wasn't.  Not only was he not sleeping through the night, he would wake up 4-6 times a night.  Finally, we had enough.  We followed our Doctor's advice and let him cry.  After 4 painful nights, he is sleeping very soundly from about 7:30pm to 6:30 am.  It is very hard to listen to your baby cry, sometimes up to 30 minutes or longer, but your baby "knows" that if he cries long enough usually you will come get him.  You have to break this cycle.  Do listen to the way your babies cries.  Is it his usual, "I'm awake, come get me" cry, or does he/she sound distressed, wet, or dirty. A few times I have had to get up, just to change his diaper, but YOU DO NOT TALK to him and put him immediately back in bed.   This may seem mean, but talking to your child in the night, reinforces him wanting to be up with you. 

My son and 4 year old daughter share a room, so another problem is he wakes her up at night crying.  We solved this, by telling her to come get in bed with us when he cries and wakes her up.  We would either let her in our bed or we made a "bed" for her on the floor.  She usually went immediately back to sleep, and we would move her back to her bed as soon as the baby had stopped crying and went back to sleep. 

What I have learned is "a well rested child sleeps better and longer", and this is the truth. The more my son sleeps, the better he sleeps.  The key to all of this is consistency.  The baby must have a consistent bedtime, and you must be consistent also. 

I hope this helps someone.  I know this advice helped me because I know have a happy, well rested son.

Kerri Sweatman