International Music Score Library Project
From Wikipedia, the free encyclopedia
International Music Score Library Project (IMSLP) is an internet-based project to create a virtual library of musical scores which are in the public domain. It will also encompass scores from composers who are willing to share their music without charge.
IMSLP is based on wiki software.
Mutopia project is a similar undertaking, the difference being that Mutopia always re-typesets scores, whereas IMSLP accepts (and is mostly made up of) scans.