Yahoo! Audio Search

Yahoo Audio will not include songs from file-sharing sites such as Kazaa and Grokster, which are often used to trade copyrighted music. If a record label complains about any song featured on the site, Yahoo Audio will take it off the list. (According to USA Today)

Updated: Yahoo is NOT the first one with such a meta-search and rev share service: San Francisco based GoFish Technologies has had a similar compare-and-buy service for some time now.