Resources for Genres
Classical
Classical Net 
Nice starting spot for the neophyte. Contains lists of basic repertoire, CDs, reviews, lists of books & scores, and links to other classical music sites.
Electronic Music
List of links maintained by the Music Library at Indiana University.
Electronic Music Interactive
A "music theory primer for electronic music" developed at the University of Oregon New Media Center.
Music Resources: Computer Music, MIDI, etc.
List of sites maintained by the Sibelius Academy
WWW Sites of Interest to Musicologists: Computer & Electronic Music
List of sites maintained by the American Musicological Society
Jazz Archive 
Created and housed at Hamilton College, contains 300 interviews with jazz musicians, arrangers, writers and critics. The collection generally focuses on artists associated with mainstream jazz and the swing era, and is particularly viable for material pertaining to the learning process employed by musicians prior to the establishment of jazz education programs, and the realities of making a career in the jazz world. Other significant topics addressed include stories of life on the road and in the active New York City recording scene as well as racial relations (past and present) in jazz. 282 intereviews have been transcribed, and are searchable by subject matter and key word search. Selected video excerpts may be viewed at the archive web site. Interviews are cataloged in WorldCat, and are available on loan in DVD format, from the Hamilton College Library, via Interlibrary Loan
All Music Guide: Jazz
Discography, biography, and reviews of albums. Music ratings and reviews are done by a coordinated system of free-lance writers and music experts from around the globe. Albums for each music artist are rated against their own best work and not against other artists in their genre. The result is a rating scheme that allows users to see at a glance the best (and worst) albums for any particular artist. Must drill down through music genres and sub-genres to get to performers/composers, songs, and recordings.
WWW Sites of Interest to Musicologists: Jazz
List of sites maintained by the American Musicological Society
IJS Jazz Register CASE Microfiche Research ML156.4 .J3 R94
Catalog and index (by performer, title, composer, label name) to recordings in the Institute of Jazz Studies at Rutgers University. Guide filed with fiche. Produced quarterly, each edition was cumulative and superseded previous ed. July 1988 edition.
European Free Improvisation Pages
Begun in January 1995, EFIP was intended to be a comprehensive information resource for all aspects of the type of music known as European free improvisation. Particularly useful for European biographical information.
Internet Broadway Database
Searchable database created by the League of American Theatres and Producers' Research Dept. Provides records of productions from the beginnings of New York theatre until today. Details include pertinent people involved as well as interesting facts and production statistics.
Rock Music Scholarship: an interdisciplinary bibliography
Case Reference ML128.R6 G37 1995
List of articles and books about Rock Music. Published in 1995.
Literature of Rock 1974-78
Case Reference ML 128.R6 H6
Bibliography of books and articles about rock music.
Literature of Rock 1979-1983
Case Reference ML 128.R6 H62
Continuation of previous title.
All Music Guide: Rock
Discography, biography, and reviews of albums. Music ratings and reviews are done by a coordinated system of free-lance writers and music experts from around the globe. Albums for each music artist are rated against their own best work and not against other artists in their genre. The result is a rating scheme that allows users to see at a glance the best (and worst) albums for any particular artist. Must drill down through music genres and sub-genres to get to performers/composers, songs, and recordings.
History of Rock 'n' Roll
The Golden Decade 1954-1963.
Rock 'n Roll Hall of Fame
The official website with visitor info, exhibit highlights and articles (click on Backstage pass).