International Music Score Library Project (IMSLP)--free public domain copies of classical music that is out of copyright
Woodwind.org--resource primarily for clarinet players, but also contains a discussion board for other instruments
Sheetmusicplus.com--where we order most of our sheet music when it's not available locally
Music in Motion--fun music gifts and accessory site, many items not available at any other site
Piano Society--lots of free mp3s of many of the piano pieces elementary and intermediate students study
Piano World--lots of resources for people who want to learn a lot about the piano
Royal Conservatory of Music Examinations--where we send many of our students to do exams with
Practicespot--lots of great music resources for music students, music parents, and teachers.
MusicTheory.net--A great online music theory site, with lessons and tutorials, which you can customize.