Specializations are gained through an examination process after someone has become a registered nurse. You will need to apply for a NCLEX exam to the appropriate board of nursing. Residency programs in pediatrics offer slots of time dedicated to NICU care and employers can offer and provide additional education and/or training. You can't graduate as a NICU nurse per se (post-grad degrees aside); it's a very technical field and I'd recommend that you focus more on completing your pre-reqs. The one proactive step that you could take now is focusing yourself slightly more on pediatrics.
Essentially the path to NICU certification is to:
1. initially get your BSN
2. Apply for the NCLEX and get approved to take the test
3. either attend a post-grad program or begin working and gain hands-on experience
4. Complete a post-grad residency in pediatrics or convince your employer to provide you with additional training
5. Pass the test
To learn some more about Neonatal Intensive Care you could check here: http://education-portal.com/articles...ng_Career.html
Taking some online classes may also help, which can be seen here: http://www.onlinenursingschools.com/
Good luck