by Gina Trapani Your digital music collection is crying out for new songs. Sure you could hit up the iTunes Music Store, or rip another CD, or fire up your P2P software and pray the RIAA doesn't eat your firstborn - but the plain ol' web is an untapped goldmine of audio. If you're willing to branch out beyond the Top 40, have a gander at six of my favorite places to find tunes on the web. GoogleUs