Here is what we have been doing since DS was about a month old.
Bath (every other night)
Then if he is still wide away we read him a story.
We used to have to rock him, but now we can just put him down and he soothes himself to sleep.
My Pedi says right around 4 months is when babies start to develop habits (good and bad). Until DS is alittle older we will give him a bottle right before bed. We try not to let him fall asleep on the bottle, I think that is what they are refereing to as bad behavior. He doesn't fall asleep on the bottle during the day (the only exception to this is if he has refused to nap for hours, but needs a bottle...I still try not to let him fall asleep ON the bottle when this is the case).