Petrucci Music Library- Free Classical Music Library

The Petrucci Music Library is an internet-based collaborative music score library, and is currently the main project. You will find tens of thousands of scores composed by thousands of composers here, all available for free download.

Our goal is to create a virtual library containing all public domain music scores, as well as scores from composers who are willing to share their music with the world without charge. The Petrucci Music Library also encourages the exchange of musical ideas, both in the form of musical works and in their analysis. Feel free to post your analysis of a particular piece on the "discussion" pages, or join our forums for interactive discussion with the community.

Website:
http://imslp.org/wiki/