Everyone kind of has a different view of what is appropriate with teaching your children how to sleep. I actually was sold on training her from birth on with the sleep-eat-play routine, but with all her eating issues, that didn't work. We had to feed her as much as possible and she often fell asleep eating.
But, with K and C, I had a pediatrician that was huge on letting your babies cry it out. When K was five months old, we began. As a young mom, I just did what I was told and let her cry. It worked. 45 minutes the first night. 20 the second. Less than 5 every night after. And she was happier. It was good.
With V, her growing issues, the shape of our house, and (I hate to admit this...) she probably is a little spoiled being the youngest of so many...we have rocked her to sleep and sometimes even nursed her to sleep. But, it isn't really working any more. She is so tired sometimes and just will not succumb and allow herself to fall asleep.
So....she is crying herself to sleep. It breaks this Mama's heart. I hate that she feels abandoned. I hate that she is mad and/or scared. But...I know she will be better with the ability to fall asleep. I wonder if this is how our Heavenly Father feels when He has to let us go through hard things where we feel abandoned or alone or mad or scared. He knows that we will be better. He knows that it will improve our life. And He probably hates that we feels so abandoned and scared, but He loves us enough to let us go through it.
Update (4/23/13): She has now had three naps and two nights. The naps she has cried for less than five minutes each time, including no crying at all this morning (a little whining, but no crying). The first night she cried for about 16 minutes, the second about 12. She is getting this and she is sleeping so much better. She is happier getting enough sleep (aren't we all?!?). It is working REALLY well for her. I am a happy Mama.