Free public domain music for download

Note that some sites require registration

8Notes

AirTurn Free Sheet Music Resources

Boosey & Hawkes

ChristmasCarols

Classical Music Scores -Russian

EveryNote

FreeHandMusic - not sure if it's PDF

IMSLP

Munich Digitization Center

MusOpen

NTYTimes about IMSLP

Sheet Music Archive

Virtual Sheet Music

WrittenMelodies

 

What you need to know about the copyright law

Copyright 101 - Fair Use

Copyright Law