Hi Maggie,
I've also posted to this in the other section. I found some names of books that might help: "the no cry sleep solution" someone posted about this book in this forum so maybe borrow from a library and check it out and also Pinky McKays book, "Sleeping like a baby" offers a 4 week plan to wean baby off the breast for sleep to using other sleep cues but she does say not to use in babies under 4 months. Just remember if you are happy at the moment go with the flow.
This whole debate came up with my in-laws last night, I ended up in tears cause they pretty much attacked me for the way I parent, they basically told me I have to leave her to cry and not let her run the place etc etc. I have no prob letting Ash fall asleep on the breast or rock her to sleep so I don't understand why its a prob to them.