Here is a break down of the different departments:
Pediatrics: must be an RN and you will care for infants, children and teenagers.
Maternal & Child health: you will work with pregnant women, and newborns.
NICU: advanced education to take care of critically ill infants.

There might be more but these are what I'm aware of.
Good Luck!

As far as schooling goes you should first become a registered nurse. You then can take extra classes for various specializations. Pediatrics requires a 2 year masters degree. This will let you work in hospitals, clinics and schools. Midwifery requires a masters. NICU you must first be a nurse practitioner. You will then take the necessary classes such as infant medical treatment. Do some research online there is a lot of information out there.

Working with children
First, you do not have to be a nurse practitioner to work in Neonatal Intensive Care Units. Only if you are wanting to be an ARNP in that specialty. Most larger cities with children's hospitals offer internships to graduates in the NICU, Pediatric ICU, and other areas such as operating room. If you have to work through school, I recommend checking your local hospital for any position that will allow you to go to school. Many hospital offer tuition reimbursement and scholarships through the hospital foundation,etc. Pursue your dream.

NICU Nurse
Hello. I am a NICU nurse. I am a travel nurse as well. I spent 9 years in the Navy as a medic, while I was going to nursing school at the same time. I graduated nursing school in 2001 and started working as a graduate nurse in training in JAN 2002. With 2 years experience in NICU, I decided to go traveling. I travel with my Navy retired husband and my 3 year old and my 1 year old. Now, I am considering becoming a NNP (neonatal nurse practicioner)., FOLLOW YOUR DREAMS.

which school you are going, I will start this Fall in Yonker.

I am interested in the same area as you
I am looking to start out in maternity and work my way up to CNM. I hope that your desires will fall into place! Stay in touch and maybe we can go through this process together!

Good Luck

Mt Washington Pediatric Hospital in Baltimore has a "TICU" for the little guys out of NICU that are not cleared for infant nursery.