Popular Music Studies Database - Thousands of popular music publications in several languages, listed by University of Montreal music educator Philip Tagg between 1984 and 2006 and moved to new server in 2007 with help of Italian web designer Carlo Ercole. Text searchable by author, titl - http://www.carloercole.com/tagg/
Wikipedia: Popular music - Definition with discussion of disagreement over relative value of popular and art music. List of reference articles. - http://en.wikipedia.org/wiki/Popular_music
Experience Music Project - Music museum in Seattle, Washington, named for the band of Jimi Hendrix, offers biographies, audios and videos on pop music stars as well as tutorials on multi-track recording and songwriting, interactive guitar lessons, a gallery of poster art and shoppi - http://www.emplive.com/