Pop and Rock

Brillsongs.com
Promotional showcase for songwriters by UK-based Hilltop Publishing Ltd. offering audio samples of their writers by genre as well as songwriting to order.
http://www.brillsongs.com/

Carlin America
Independent music publishing conglomerate, with a catalog of pop, rock, country, showtune and standard songs.
http://www.carlinamerica.com/

Cherry Lane Music Group
[New York] Sheet music and books about pop and rock music.
http://www.cherrylane.com/

MPL Communications
Publishes popular music.
http://www.mplcommunications.com/

Tic Toc Tunes, Inc.
Features the catalogue of songwriter Jay M. Kinkade III. Includes biography and audio examples.
http://www.tictoctunes.com/