Instrument Studies for Eyes and Ears – Jacobs School of Music
- a great website for understanding ranges and tendencies of instruments
- useful for general orchestration techniques
- can hear instruments tone color in ranges and with different articulation.
MuseScore | Free music composition and notation software
IMSLP
- massive resource for score study
- contains scores written before 1923.
musictheory.net
- theory practice and ear training
Oxford Music Online
- contains Grove Music Online
- dictionary/encyclopedia