Other
Music Theory First Aid for Struggling Students
This site provides music theory information on such topics as rhythm, intervals, scales, chords, etc. Also, there is a fine section which describes the basic concepts of form and structure.
Music Theory
Music theory.net
An online beginning music theory and ear training site. This site is for students to use at home to reinforce what they learn in class.
Music Education
Learning to Read Music: Basic Counting, Part 2
Beginning musicians can practice reading notes and counting beats using this resource that also provides several lines of music with different types of notes, rests, and time signatures.
Music Education
Music Education: Introduction to Reading Music
A very simple explanation of the very basics of music reading. This is really good for the singer who wants to understand more about what is on the musical page. Not very advanced- very basic.
Other
Music Concepts Online: Notation: Basic Rhythm and Pitch
This site looks at rhythm, terms and concepts, which include rhythm, score, note (parts of and kinds), rests, tie. Great information.
Open Curriculum
Open Curriculum: Pitch: Sharp, Flat, and Natural Notes
To understand the definition of a pitch, its effect on notes, and the associated symbols.