Nat Geo music is the go-to website if you are researching or just interested in World Music. Its homepage content is dynamic and changes daily. It includes video and a free song download of the week. There is even a pop- player radio that will let you stream music.
This is a great resource if you are looking for folk music. It includes Cajun, Blues, Carribbean, Celtic, India, and a little of everything. It is easy to think of folk music in the terms of a bearded man and his acoustic guitar, but this website encompasses musical traditions that span the globe.