All Music Guide
Albums, song titles, and artist biographies are included, but not all are rated.
Ultimate Rock Cyclopedia
Internet's largest rock music encyclopedia lists artists/groups with session details, biographies, photos, and links.
Historical American Sheet Music
Project presents digital images of sheet music from Duke University's collection. Published between 1850 and 1920, highlights of the collection include, "antebellum southern music, Confederate imprints, Civil War songs. Searchable by composer, title, performer, and many other terms.
DW3 Classical Music Resources
Duke University cite has linked to about 1700 noncommercial pages/sites in more than a dozen languages. Sections like Composer Homepages or Genre-Specific Pages lead to annotated links.