Are you not sure what song that is playing on the radio or on TV? Crack open Shazam and hold it near the source long enough for the free app to get a fix--about 30 seconds. Shazam compares the recorded song with music in its database and will return a match to your song. In Shazam lingo, this is "tagging" a song, identifying its name and artist. Shazam for Android remembers the music you tag and gives you a chance to buy it yourself via the Amazon MP3 store on your phone. If you can't get enough of the song, you can also watch a YouTube video, if there's one available. A tie-in with MySpace also gets you close to the band if they have a page there.
Compared with Shazam on other mobile platforms, this version is still behind on features, like watching trends, though for casual users, it's fully functional as is. Just don't expect Shazam to pick up your own warbling. It works on recorded music only.