SeeqPod
There might be a cornucopia of free music online, but because the Internet's so overloaded with other, crappier cornucopias (crezdit reports, books), those songs can be harder to uncover than the root of your illicit love for Billy Ocean. Mine tunes from the Web's darkest recesses with SeeqPod.
Pioneers in "playable search," SP combs blogs, personal sites, and anywhere else an mp3 could hide to return a list of songs you can play right from the results page (sparing you a bone-chilling visit to the webpage of a man who hosts troves of L.A. Guns). Beyond locating individual tracks, SP's coolest feature is its playlist creator, which lets you store your illicit bounty, preserving the links until the RIAA kicks in the door of the fat nerd you're streaming those showtunes from. There's also an impressively accurate recommendation engine that uses preferencing algorithms and human input to tell you that if you like Eagles of Death Metal you'll also like Sluts of Trust (and if you like Jefferson Airplane, you'll love Jefferson Starship).
Other SeeqPod features: video searches, links to lyrics, tour dates, and ringtone downloads, plus "check out my playlist" invite emails and an embed code for posting the mix on your personal homepage -- so now other music lovers can wade through a tangle of crezdit to reach your newfound bootleg copy of "Caribbean Queen," Live In Omaha.