Are there any good books for parents on adding a new sibling into the family?
Either of these books would be helpful to read while you are expecting your second (or third) child. Both address many issues, including parents’ feelings about a second pregnancy; helping your firstborn adjust; understanding rivalry issues; the father's role; setting up a family birth plan; and managing two or more kids while sustaining your marriage.
From One Child to Two: What to Expect, How to Cope, and How to Enjoy Your Growing Family, by Judy Dunn.
And Baby Makes Four : Welcoming a Second Child into the Family, by Hilory Wagner