There are literally hundreds of websites that offer free sheet music and a large percentage (not ALL) of the titles are also copyright-free so you can arrange, transpose or transform the original to your heart’s content.

Music Prodigy Core makes practice and assessments easier. Instant red note/green note evaluation as students playA comprehensive solution for all voices, strings, percussion, winds, guitar, piano (patented polyphonic pitch recognition system)All student levels, general music through universityNo external microphone requiredIncludes thousands of music titlesNo training requiredTeacher classroom dashboard with pre-formatted student progress reportsiPhone, iPad, Android phones and tablets, Windows PCs, Mac OS X, and Amazon Kindle Fire

An online game that allows students to practice note names, fingerings, and musical terms.

Websites with music available in XML format