This website provides information about hammered dulcimer events in the Michigan area, where this is a very high concentration of interest for this particular instrument. There is also a repository of sheet music and midi files for traditional and original (tradtionally inspired) songs as well as links to various other resources within and outside of the hammered dulcimer community.
DLA music entries are derived from non-commercial sound recordings that document much of Appalachian music's geographic, ethnic, vocal, and instrumental diversity. The several thousand presently available provide an unprecedented resource for study of repertoire, technique, lore, and the musical interchanges among the region's traditional musicians, many of who are no longer living.
This is a search engine that is tuned to finding music on the web. Are you looking for sheet music, ABC format or a MIDI file for a particular tune? Give this a try.
This site contains a good collection of fiddle tunes, all available as PDF files with fairly clean notation. An added benefit are the associated MIDI files to play along with.
The MudCat offers up blues and folk music. They provide lyrics, MIDI files, forums and some handy how-to guides.