Green Linnet Folk, Celtic and roots music. Shanachie Entertainment Folk, blues, jazz and world music. Irish traditional and classical. Very popular and extensive site covering Celtic music, artists, links, etc. Claims to be the largest online collection of information on celtic music, and has links to hundreds of related sites.
Current popularity is over half a million hits per month.
Folk Roots magazine Online version of the popular magazine. Covers folk and roots music and includes features on artists, festivals, new recordings and current related topics. Musical Traditions Extensive links source. Links cover a wide range of folk and traditional music interests, including some quite obscure and narrow-interest ones. Nail's English Folk Music Extensive links source.