The International Council for Traditional Music is a scholarly organization which aims to further the study, practice, documentation, preservation, and dissemination of traditional music and dance of all countries. To these ends the Council organizes World Conferences, Symposia, Colloquia, and publish a yearbook and an online bulletin.
A site full of great information about the history of recordings and their pioneers. It has an emphasis on the Eastern Mediterranean; especially Greece and Turkey about the period from 1900 till 1940.
The Meertens Institute, established in 1926, has been a research institute of the Royal Netherlands Academy of Arts and Sciences (KNAW) since 1952. We study the diversity in language and culture in the Netherlands. Part of the Meertens Institute is the Amsterdam Center for European Ethnology Very interesting is also the Dutch song database http://www.liederenbank.nl/index.php?lan=en.
The site of Dimitrije Buzarovski (Buzarovski Archive). A lot of information about (musical) developments related to Balkan cultures and traditions.
A site of excellent information about music on 78RPM shellac records.
The site of "Macedonian Folk Songs" with hundreds of song texts, audio samples and somtimes translations.
Site of Tom Deering, who unfortunately passed away last month, with a lot of information about recordings of traditional music.