link harvest (mostly known)

daily:

artsjournal: the daily digest of arts, culture & ideas

arts & letters daily: philosophy, aesthetics, literature, language, ideas, criticism, culture, history, music, art, trends, breakthroughs, disputes, gossip. and all of this updated on a daily basis

rec.music.classical.contemporary

monthly:

la scena musicale on-line: a free monthly magazine published in english and french by la sc‚àö√£ne musicale/the music scene, a non-profit organization dedicated to the promotion of classical music

also:

artnet