If you have a favorite Internet site for music research that isn't listed here, please let me know about it!
Petrucci Music Library / IMSLP: The free public domain music library, from the International Music Score Library Project.
WWW Sites of Interest to Musicologists from the American Musicological Society American Musicological Society's page -- Links to a very broad range of music-related websites.
Digital Mozart Edition This is a reproduction of the new collected edition of Mozart's works (the Neue Mozart-Ausgabe) in a digitized format, which enables scholars and performers to peruse Mozart's music on the Internet.
Library of Congress Classification System for Music This resource can help you learn to browse the music collection more efficiently.
YouTube Offers an ever-expanding but not very authoritative nor user-friendly selection of videos including musical performances
Performing Arts Encyclopedia Explore music, theater, and dance at the Library of Congress.
OnMusic Dictionary Includes audio clips for pronunciations and sound examples. The successor of former Virginia Tech Multimedia Music Dictionary. Created and co-edited by Richard Cole (Virginia Tech Department of Music) and Ed Schwartz (VT Learning Technologies).
Internet Resources in Music: The libraries of the University of California-Santa Barbara have created this collection of links to useful sites in music theory, history, popular and classical music, and so on.
MusicTheory.net: This site, created by a software engineer, contains short tutorials on understanding how music works. The tutorials cover key signatures, notes, major and minor scales, chords, and more.
NAfME (The National Association for Music Education, formerly called MENC). A very important resource, particularly for Music Education students.
Blank sheet music paper Several different formats available; from Flutetunes..
Library of Congress Library of Congress includes on their website a wonderful and varied collection of resources of use to researchers in the performing arts. Explore the American Memory Project, Performing Arts Encyclopedia, Sound Recordings, American Folklife Center, etc. for sheet music, historic manuscripts and photographs, sound and video recordings and more.
Bassoon.org Resources and information for bassoonists -- caution, last updated 2008 and author is not stated.