Finding Scores the quick way

For someone who prides herself in being (somewhat) techno-savvy, I can't believe I missed the boat on this one!  A student came to her lesson yesterday with reams of music - nice, clean copies of Mozart, Chausson and the like.  When I asked her where she got it, she said "on-line".  Well, duh...why didn't I think of that? All that public domain music out there to be sorted and organized and, wait for it, Petrucci Music Library has done it for you! Here is what they have to say about themselves:

Our goal is to create a virtual library containing all public domain music, as well as music from composers who are willing to share their work 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'm sure you already knew about them but if you didn't, their web address is www.imslp.org  They will be your life saver when you can't get to the library!