If you are a registered nurse, earning a Bachelor of Science in Nursing degree, or BSN, will enable you to climb up the career ladder into a supervisory role. If you wish to get into the area of nursing administration, nursing education, or specialty nursing, however, you'll need to earn a Master of Science in Nursing, or MSN.
In order to apply to a Master of Science in a nursing program, you will need to have earned satisfactory scores on the GRE in addition to your BSN degree. As the MSN degree is not a purely academic qualification, you will also need a current RN license and a certain level of clinical experience.
Earning the MSN will usually take an additional 40 credits above and beyond your bachelor's-level education. The MSN program usually involves a high degree of research, as well as required nursing classes and clinical work, and you may need to write and defend a thesis or complete some type of final project. An MSN program can usually be completed in 18 months to two years of full-time study, and will not only allow you to advance in the field of nursing, but will also enable you to pursue doctorate-level nursing studies should you be so inclined.