i would definatly recomend getting elizabeth pantley no cry sleep solutions for toddlers.

she recomends starting the sleep routine at about 5 so they are in bed by 7
thats is dinner bath, books....ect

i would also recomend you DH taking over some of the night parenting so that your son is used to it when your bub comes along as if your feeding the baby you cant tend to him aswell.

there is nothing wrong with him sleeping with you(even when you have baby) it will make him feel more secure too