Introduction to Reading Music
http://datadragon.com/education/reading/
Discussion of the basic elements of notation is expanded at this site to include information on time signatures, counting, and note shape symbols.

Musical Notation
http://en.wikipedia.org/wiki/Musical_notation#Elements_of_the_staff
This online free encyclopedia offers a detailed article on musical notation and various historical notation styles.

Notation
http://www.mmissary.com/theory/theory4.jpg

Table of musical pitch
http://www.music.vt.edu/musicdictionary/appendix/pitch/pitch.html

Musical instrument pitch ranges
http://educ.queensu.ca/~fmc/november2002/MusicalPitch.html

Notation of musical dynamics
http://www.bbc.co.uk/schools/gcsebitesize/music/musicalelements/notationrev8.shtml
http://www.music.vt.edu/musicdictionary/appendix/dynamics/dynamics.html

Notation of rhythms
http://www.bbc.co.uk/schools/gcsebitesize/music/musicalelements/notationrev6.shtml

Treble and bass clef
http://www.free-online-piano-lessons.com/piano-notes.html