Music Sheaf - Contains an extensive selection of downloadable manuscript staff paper available in several formats. Visitors can design their own music paper in a variety of shapes including letter, ledger, and A4. Nissimo - You can print free sheet music of high quality. Also a forum for interpreting sheet music. Petrucci Project, The - A project to digitize public domain sheet music.
Some scores are available.
Ragtime Sheet Music and Books - A source for ragtime music. Includes some downloadable tunes in GIF format. Score On Line - Downloadable PDF scores. Some free, most cost money. Original compositions accepted.