Good Ear  
   Online ear training site.
   http://www.good-ear.com/

Practical Music Theory  
   Includes software, books, exercises, and links.
   http://www.teoria.com/

Theory of Music with Ted Kirk  
   Resources for learning and teaching music theory to grade 5 of the Associated Board (UK).
   http://home.clara.net/tedkirk/theory.html

Polytonic Harmony  
   Allows for the creation of music in multiple, simultaneous keys as well as a practical method of voice-leading these chords.
   http://www.erols.com/wbeachy/

The Anatomy of a Fugue  
   An outline of the substantials of a fugue based on Hugo Norden's "Foundation Studies in Fugue." Topics include counterpoint, subject, answer, and stretto.
   http://musik.freepage.de/cpb7079/inhalt.html

The Tonal Centre - Tonality  
   Interactive site for music composers and theorists which explains and demonstrates some of the key concepts of tonality; including chords, scales, cadences, and modulation.
   http://www.andymilne.dial.pipex.com/

Gary Ewer's Easy Music Theory  
   Includes 25 lessons on music theory, including scales, transposition, intervals, and score formats.
   http://musictheory.halifax.ns.ca/

Fred Lerdahl's Attack on Serialism  
   Discussion of Lerdahl's published article "Cognitive Constraints on Compositional Systems", which explores the relationship between composing and listening.
   http://music.dartmouth.edu/~kov/lerdahl/

Ricci Adams' Musictheory.net  
   Includes introductory and intermediate music theory lessons, ear trainers, and books.
   http://www.musictheory.net/

Star Theory  
   Free preparatory syllabus in music theory and orchestration.
   http://www.musicarrangers.com/star-theory/

Multimedia Music Theory Tutorial  
   A concise summary of important concepts in music.
   http://www.chordwizard.com/theory.html

Bimodalism, A New Dimension and Ethos in Harmony  
   Contemporary alternative to atonal styles of composition.
   http://www.ubieta.com/bimodalism/

WholeARTS Music Conservatory  
   Introductory dialogue for courses in music theory and composition.
   http://www.wholarts.com/music/ed/intro.htm

Syntactic Structures in Music  
   By Tom Sutcliffe. Aims to help students of music theory understand the role of chord progressions in musical structures. Site includes animated demos.
   http://www.harmony.org.uk

The Society for Music Theory  
   Includes a database of journal article from the SMT Journal.
   http://societymusictheory.org

Zeuxilogy  
   A new theory of musical time, developed in the past twelve years by the music theorist Andrei Pogorilowski.
   http://www.zeuxilogy.home.ro/

AP Music Theory  
   Information about studying for and taking the advanced placement music theory exam.
   http://www.collegeboard.org/ap/music/index.html

Eric's Treasure Trove of Music  
   A reference resource on music theory, covering in brief a vast array of topics.
   http://www.treasure-troves.com/music/

Rhythm Exercises  
   Notation for drills, rudiments and etudes for practicing rhythm. By Nick Marshall.
   http://www.izap.com/~pinnacle/rhythms/

Java Music Theory  
   Suite of Java applets designed to help students of music theory improve their proficiency at basic music theory skills.
   http://academics.hamilton.edu/music/spellman/JavaMusic/default.html

Mr B's Music Tutorial  
   By a music educator for students, a guide to self study covering music reading, piano, guitar, composers, and music history.
   http://schoolnotes.com/02910/mrbsmusic.html

Fundamentals of Raga  
   Introduction to the Indian modal form known as "rag" or "raga".
   http://chandrakantha.com/articles/indian_music/raga.html

Elements of Music Notation  
   Basic introduction to reading music. Learn note names, clefs, staff, signs. Worksheets and answer keys included.
   http://www.lessontutor.com/eesMusic1.html

Harmonic Bindings  
   A paper about the unification of Janeãek's theory of imaginary tones with the two Risinger's principles of functional relations.
   http://www.sweb.cz/vladimir_ladma/english/music/articles/ifsa97.htm

The Basics of Reading Music  
   Online tutorial by Kevin Meixner.
   http://www.notationmachine.com/how_to_read_sheetmusic/readingmusic.htm

Gems of Compositional Wisdom  
   Articles on advanced atonal and serial concepts.
   http://www.cosmoedu.net/DoctorFields/

Lunar Calendar Theory of Music  
   Walter Johnson demonstrates similarities between the DO, RE, MI scale of music and the ancient Athenian lunar calendar of Meton, the Fibonacci rabbit sequence, and the annual spawning cycle of coral.
   http://walterjjohnson.com

Technical Committee on Musical Acoustics  
   A group within the Acoustical Society of America, that concerns itself with the application of science and technology to the field of music. Contains members, a list of papers, acousticians and links.
   http://www.public.coe.edu/~jcotting/tcmu/

Solomon's Music Theory and Composition Resources  
   Resources for composers, music theorists, and researchers of music, with sound files, papers and compositions.
   http://music.theory.home.att.net/

SchenkerGuide  
   An introduction to Schenkerian analysis for undergraduate music students. Includes background, working method, glossary and bibliography.
   http://www.schenkerguide.com/

Music Theory Online  
   Offering a musical dictionary, recorder lessons, instrument information and a composers listing.
   http://www.dolmetsch.com/theoryintro.htm

Chiasmata Modality  
   An experimental modality.
   http://www.geocities.com/sz1_emery/index.html