Music Theory
Music theory.net: Rest Duration
A wonderful resource for teachers and students! Gives examples and explanations of rests and how they affect the sound of a musical piece. Simple illustrations and explanations make this animated site easy to follow.
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.
Open Curriculum
Open Curriculum: Duration: Rest Length
Explains the different types of rests and their effect on the music.
Music Education
Learning to Read Music: Types of Rests
This tutorial teaches students the different kinds and values of rests in music notation.