a. Take out a reasonably valued life insurance policy for each of you (parents) based on your lifestyle. You never know what can happen, but if it does, G-d forbid, at least the other spouse will not be left in a complete free-fall while raising a baby on his or her own.
b. Put aside a rainy day fund of 6-12 months of (your combined) salary. What if one of you gets fired or decides to quit a job?
c. Review and update (or create) your financial plan to understand your current spending and project increases in what you will need to spend with the baby around.
Budget appropriately for formula and other food, clothing, daycare/nanny, stroller(s), transportation, decreased income (due to time off for Mommy and/or Daddy). Don't be caught off-guard.
Project out the costs (lost income and/or benefits) of staying at home vs. returning to work, how long each of you can stay at home with the baby.
d. Take the opportunity to reviews your finances and taxes to maximize all advantages, whether by earning points from your credit card purchases, maximizing your employer's 401(k) or Roth IRA contributions, negotiating down fees and recurring expenses (phone, internet, cable).
e. Go into the birth with clear eyes about how you will pay for what and where the money will come from. Have a safety cushion and hedge your risk appropriately. Don't be caught off guard by "circumstances."