Shazam is a music recognition app that's really useful for helping you figure out information about a song you're hearing. The app is very simple and easy to use as there's only two options for you to select from when you load it. Those options are Tag Now and My Tags.
Tag Now is the function you'll use to figure out what song you're listening to. Tap the Tag Now button and hold your phone up to the source of music. Ideally, you'll want to have as little background noise as possible, but Shazam is pretty good at weeding through all of that. Once it gathers about 15 seconds of the song, it will search it's database for more information.
If Shazam finds your song, the app will pull up a listing for the song, including the artist and a picture when available. Below the basic information listed you'll see three link. These links lead you to the bands MySpace, their Amazon.com MP3 page, and their YouTube videos. Every song you tag will be kept in your My Tags page until you remove it so you can visit it later if you're interested.
This app is really handy and works most of the time. The second example in this review was the song Coney Island by Good Old War. Unfortunately it didn't pull up any results even with the music playing right in front of the speaker.