Other
The Basics of Reading Music
This site is an overview of how to read music. The basics of notation such as note and rest values, the names of lines and spaces of both treble and bass clefs, etc. are covered. Includes downloadable audio files.
Other
Mml: Notation Module: Clef
Although very simple in its design, this short piece gives a nice overview of musical terms, one of which is the treble clef. The author briefly discusses the attribute of "key" in conjunction with the clef.