You can do an advanced library search and then limit your search to "Scores" in the Resource Type category.
By entering a keyword (band, symphony, piano) you will get a large number of results. Adding specific keywords will narrow your results significantly.
If you have a specific composer in mind, do an author search. (last name, first name)
In library catalogs, pieces of music are given added, preferred titles, so that one search finds every version of a piece.
Preferred titles (aka uniform titles) are especially useful because pieces could have:
All of our scores are located in the alcove of Murray Library near the Writing and Learning Center.
Art Song Central Free, printable sheet music for singers and voice teachers. An emphasis is placed on standard classical and traditional repertoire.
Choral Domain Public Library (CPDL) Largest sited devoted exclusively to providing free choral sheet music. More than 16,000 scores, searchable by title, composer, musical period, or genre.
Choral Scores Download "A gateway to the best free choral scores available for download on the Web. This is a Web Directory that aggregates free choral scores from the most reputable and reliable sources."
Free-scores.com Includes the ability to limit by composers' nationality, genre, and ability level.
FreeSheetMusic.net Links to sites with free sheet music. Lots of choral music and church music.
In Harmony: Sheet music from Indiana Sheet music is held in several repositories at Indiana University. This web site allows you to search some of the holdings from the Lilly Library's approximately 150,000 pieces of sheet music, including those for which there are digitized images available.
International Music Score Library Project (IMSLP) IMSLP is a free music score resource where account users collaborate by adding, removing, and editing content. Scores from nearly 14,000 composers are available to view for free.
Mutopia Project 2070 pieces of music – free to download, modify, print, copy, distribute, perform, and record – all in the Public Domain or under Creative Commons licenses.
Neue Mozart-Ausgabe (NMA) An ongoing project to digitize the complete works of Mozart and make them available. Users must agree to "fair use" principles of copyright law.
Sheet Music Consortium Joint project to digitize and make available an open collection sheet music, now over 200,000 items. Contributors are: UCLA, Library of Congress, Indiana University, Duke University, Johns Hopkins, National Library of Australia, and the University of Maine.
The Choral Public Domain Library Searchable database of close to nine thousand choral music scores available for free download. Updated daily. Also includes texts and translations.
The Lester S. Levy Collection of Sheet Music Contains more than 29,000 pieces of music and focuses on popular American music spanning the period 1780 to 1960.
UCLA Popular American Music Collection One the largest popular music collections in the country, numbering almost 450,000 pieces of sheet music, anthologies, and arrangements for band and orchestra. The collection also includes 62,500 recordings on disc, tape, and cylinder.