Sites of theoretical interest
The Society for Music Theory
http://www.societymusictheory.org
Rede Interdisciplinar de Semiótica da Música
http://www.pucsp.br/~cos-puc/rism/index.html
STM(Svensk Tidskrift för Musikforskning)-Online
http://www.musik.uu.se/ssm/stmonline
Dutch Journal of Music Theory
http://www.cva.ahk.nl/tvm
International Association for Semiotic Studies
http://IASS-AIS.org
International Semiotics Institute
http://www.isisemiotics.fi
Open Semiotics Resource Center
http://www.semioticon.com
Journal of the Royal Musical Association
http://www3.oup.co.uk/roymus
JMM: The Journal of Music and Meaning
http://www.musicandmeaning.net
The Musical Quarterly
http://www3.oup.co.uk/musqtl
Music and Letters
http://www3.oup.co.uk/musicj
Sapaan (online music theory journal)
http://www.sapaan.com
RILM - Répertoire International de Littérature Musicale
http://www.rilm.org
RIPM - Répertoire International de la Presse Musicale
http://www.nisc.com/ripm/Default.htm
A Schenkerian analysis website for university students:
http://www.schenkerguide.com
An interesting article on electronic publishing:
http://arxiv.org/blurb/pg96unesco.html
A site on tuning and scalemaking:
http://www.harmonics.com/lucy/tuning.html
A site with articles on several topics:
http://www.webster.sk.ca/greenwich
General music sites
Classical dj
http://www.classical.dj
MusicTeachers.co.uk
http://www.musicteachers.co.uk
The Art of Compromise: an essay on some of the "tricks of the trade" employed by piano accompanists, by Ian Carmalt.
http://www.pianist-kent.co.uk/accomp.html
Select My Tutor
http://www.selectmytutor.co.uk/subject/music.html