Dante Rosati's Guitar Page: Practice routines and authoritative articles on exercises, visualization, and preparation, as well as some interesting pictures.
Derek Hasted's Guitar Ensemble Pages: Lessons, hints, tips, music, sound clips, published music and other information for the classical guitarist.
Niibori Guitar World: A music academy founded by Dr. Hiroki Niibori with history, courses, Niibori orchestra concerts and recordings, publishers of Monthly Harmony, and International links. [Japanese/English]
North Carolina School of the Arts Guitar Dept.: Master of Music, Bacherlor of Music, and High School Diploma in classic guitar performance.