Valley City State University is a good online music school

Valley City State University offers an online music degree program specifically designed to meet the needs of students who are unable to study in person.

VCSU offers full Bachelor of Arts of Bachelor of Science degrees online, and holds accredidation from the National Association of Schools of Music.  Courses include private instruction in addition to courses in music theory, history, aural skills, basic conducting, music technology, piano, and scoring/arranging.  The online degree program usually takes a full four years to complete.