Reference

English-French Music Dictionary
Alphabetical listings from French to English and English to French

German-English Music Dictionary
Alphabetical listings from German to English and English to German

Grove Music Online
New Grove Dictionary of Music and Musicians online, periodically updated
Also includes: New Grove Dictionary of Opera and the New Grove Dictionary of Jazz

Metropolitan Opera
Stories of operas plus a wonderful archive of the history of the Met and its performances.

Music in Print(emusicquest)
Indexes to the music in print series for the following categories: sacred choral, classical vocal, orchestral, string, classical guitar, woodwind, and piano

Names of the Instruments and Voices in English, French, German, Italian, Russian, and Spanish
A handy quick reference to foreign music terminology

Opera Libretto
Guide to complete libretto from hundreds of operas.

Pronouncing Dictionary of Music and Musicians
From the Iowa State University WOI radio station