A good Canadian-based website that I found is IMSLP. Being Canadian-based, SOME of the available songs are not legal to download into the U.S. and some other countries/ SOME OF THE AVAILABLE SONGS ARE NOT LEGAL TO DOWNLOAD INTO THE U.S. AND SOME OTHER COUNTRIES. It has plenty of good stuff, mostly for piano (Not sure). Some later composers are a little lacking though. Definitely a must-see site.

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Sorry, forgot to post this part: The website is all classical!!! So for all of you classical music-freaks out there, (like me) then check out this website