Mocomi & Anibrain Digital Technologies
Mocomi: Types of Musical Instruments
Provides a list of musical instruments and how they work.
Other
Perfect Sound Forever: The Migration of African Music
This site discusses the migration of African music throughout the world and its influence on other cultures. It also speaks of the types of instruments used and the way in which they express the moods and feelings of their players.
Stanford University
Stanford University: Electronic Instruments
This resource provides information about a number of different types of synthesizers used from 1890 to 1980.