International Music Score Library Project / Petrucci Music Library
Throughout the Pedagogy Central website are links to music scores available online. In some cases, the score can be downloaded directly from Pedagogy Central, and in other cases, a link to the appropriate page on IMSLP is provided.
ALL SCORES ACCESSED THROUGH THE PEDAGOGY CENTRAL WEBSITE ARE PUBLIC DOMAIN. There is no violation of copyright law.
According to their website, the goal of IMSLP is “to create a virtual library containing all public domain musical scores and sheet music, 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.
I do not see IMSLP as a replacement for purchased music. As for my personal use, I rely on IMSLP as a resource for research, and for classroom teaching at the University level. I may introduce a student to a work from IMSLP, but I will always purchase a current, appropriate edition for the student to work from, to be sure that the printing and the scholarship are current.
The link to the main IMSLP page is http://imslp.org/wiki/Main_Page