IMSLP / Petrucci Music Library

Free public domain sheet music library Online since February 16, 2006 (20,868 works -- 50,260 scores -- 2,817 composers) Here's an example - I needed a score of Mozart's Dissonance Quartet. A few clicks, and the PDF was there. If I wanted parts or an arrangement - they were there, too. Apparently users can upload analyses too - which might be helpful, but normal academic guidelines apply: don't believe everything you read on the internet!

This is a collaborative project, not in the European Union. Scores are said to be in the public domain, but exercise caution and heed displayed warnings. A good source for old, out-of-copyright scores and parts. Read more about it below:-

Welcome to the Petrucci Music Library! 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. IMSLP / Petrucci Music Library