Middle Tennessee State University houses this collection of sheet music, performance documents, and other materials. The actual collections are not available online, but the catalog includes descriptions of the items.
The Hype Machine is essentially a feed of the latest MP3 music files. It does not create its own content; it simply collects content from popular blogs. The MP3s are not available for download, but the Hype Machine provides links to purchase them. The blog focuses on independent artists and is updated several times a day.
Don't forget about EMU's databases and journal holdings! In addition to searching the databases listed on the Databases tab of this guide, you can also search the journals directly related to popular music.
PopMatters is an online magazine that covers many aspects of popular culture, including television, books, and music. Their music site contains reviews of albums, music DVDs, live performances, and other formats.
A list of all music reviews housed at npr.org. NPR reviews new music releases in various ways, including through its feature Song of the Day and its show All Songs Considered. A wide variety of music genres, from rock to rap to folk, are covered.