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.

To understand the definition of a pitch, its effect on notes, and the associated symbols.

Basic music flash cards. Examples of all notes and rests with names.

This site looks at rhythm, terms and concepts, which include rhythm, score, note (parts of and kinds), rests, tie. Great information.