K.L.
I second the mom who suggested "Healthy Sleep, Happy Child" by Marc Weissbluth. I am normally not a book person, but this book saved my sanity and helped our marriage by showing us how to get some quiet time in the evening and a baby that sleeps all night. I nursed my daughter exclusively for nearly 2 years but by 8-9 months she was happily sleeping for 11 hours a night. He specifically talks about sleep cycle changes that occur right around 9 months enabling babies to easily sleep through the night so this would be a great time to read it. You don't have to read the whole book you can just skim it and read what is relevant to you right now. He also offers advice to both those who are able to do the cry it out thing and those who have a hard time with that. My girlfriends and I call it the sleep bible and it is now the standard baby shower gift. Good luck!