Musicianwages.com includes articles about how to make a living as a musician.
Musicalchairs is an online resource from the UK, featuring performance, teaching and administrative jobs for classical musicians.
Check out the Career Center/Career Glossary provided by The National Association for Music Education (NAfME).
☛ Remember: the transferable skills you will gain as a music major will also provide you with the background necessary to enter many other fields as well as postgraduate programs. See “Transferable Skills”