k12 music publishers vendor directorySheet Music Consortium http://digital2.library.ucla.edu/sheetmusic/
For those who love everything from Sousa to show tunes, the Sheet Music Consortium is a fabulous find. The Consortium is comprised of a number of member libraries (including UCLA) who are interested in building "an open collection of digitized sheet music." Their work has been supported by the Institute of Museum and Library Services and currently offers cross collection searching of 22 sheet music collections, with a total of 226,000 items. Visitors can click on the Virtual Collection to get started with offerings such as "Texas Cowboy Songs" and "The Titanic." The Browse feature is a great way to get a sense of the materials here. Finally, the Activity Stream provides an updated list of the most recently added items for general consumption.
Music publishers association http://www.mpa.org/directories/