Music files, sheet music, tools...
Thousand of free choir scores to download
IMSLP Petrucci Music Library (International Music Score Library Project)
A very rich library with sheet music and recordings. Here you will find over 200 000 cataloged works of music free to use. The quality of the scans is good. Most titles are professional editions which have passed into public domain.
VARIATIONS Online Musical Scores
A rich library with music from many centuries. For example you will find classical symphonies, operas, chamber music and songs here.
Learning music
is a thorough site with many opportunities for ear training. Separate training modules.