reddit Classical Guitar forum - Lively discussions about all aspects of Classical Guitar.
Delcamp Classical Guitar forum - Huge site featuring sheet music, technique, luthiers, and lessons.
Music Animation Machine - Windows Freeware that animates MIDI files. Gives a new perspective on famous compositions.
Sight Reading - All levels of sight-reading exercises in PDF format.
Classical Guitar Blog - Good selection of interviews, practice tips, and general information about classical guitar.