Bad news from Erica Sadun. The application “Listen.app” is cancelled, due to various problems. Listen.app gave you the possibility to send a piece of music to a database, which tried to identify it and give you appropriate information on it.
Here are what Erica Sadun said:
After talking to Gracenote, I have discovered several things. First, that their Track ID service is not available for noncommercial licensing. Second, that the costs for commercial licensing is beyond the amount to which I can possibly be committed to.
If you don’t mind spending $1 a shot, you can use your iPhone for music ID. Dial #43 (that is #ID). You won’t be charged for songs that the service fails to identify.