-By Antony Bruno, Billboard

MTV unveiled an online music guide designed to help viewers learn more about the music they hear on MTV channels. Soundtrack.mtv.com is a real-time listing of all the music being played on every MTV show and every MTV channel, including the short music clips heard as the soundtrack for such shows as "The Hills," "The Real World" and "My Super Sweet Sixteen."

The guide also will keep archives of all songs played as of Wednesday's launch -- providing listings by day, show and time -- as well as a look ahead to what songs will be played in the next 24 hours.

Going further, MTV will allow viewers to play 30-second clips of each song discovered via the guide, as well as link through to a more robust artist profile page where fans can listen to songs in full, view music videos and see other details about the performer.

MTV is positioning the Soundtrack site as a music discovery tool first and foremost, touting the 1,500 songs featured in its shows every week, not including music videos, across all channels.

"We are playing more music than we ever have in our entire history," says Amy Doyle, senior vp music and talent.

But MTV also is angling the site as a forum for new artists to promote themselves. Artists will have the opportunity to create their own profile pages, where they can upload as much music as they like for fans to stream, post videos and promote upcoming events. A soundtrack ratings system will rank artists and songs that receive the most votes from fans on the site.

These profiles are open to all artists, not just those with music currently airing on MTV.