Holy crap. This site rules. Emeryville-based SeeqPod "crawls" the web for MP3s and aggregates them live onto its blog. Simply search for the name of the artist you're looking for, click the green arrow to add the song to your playlist, and listen instantly (without downloading or signing up) for free. Though still in beta form (not all the links work or are labeled properly), the site is extremely user-friendly and provides hours of free, legal listening fun. Perhaps best of all is the recommendation feature, which allows you to find similar artists by typing in the name of a band you like (it's actually fairly accurate, unlike Pandora). Go there now and take advantage before it starts charging. My music collection is expanding rapidly.