When needing information about various careers, you might first try the Occupational Outlook Handbook
<http://www.bls.gov/ooh/>.
This online resource from the Bureau of Labor Statistics offers information about hundreds of careers, including entry-level education requirements, median pay, the projected number of new jobs, and job growth rates.
One can also find e-books related to specific careers. Try a search in Ebook Central using search terms for your career of choice (career nurse or nursing, for example).
Journal and magazine articles about careers can be found in Academic Search Complete, an EBSCOhost collection of publications. Try searching for information about the career of your choice there as well.