Identifying music tracks has become easy when Sony Ericsson presented its application named TrackID. Later this application ceased to exist, and currently the largest applications on the market operating on a similar basis as TrackID are Shazam and SoundHound. In the nearest future there is a chance that first from mentioned apps, Shazam, won't be separate app because Apple wants to buy rights to it.
How it was reported by some journalists, Apple already bought Shazam for 400 million of dollars. If that's true, price isn't so big as it could have been two years ago, when Shazam was valued around 1 billion of dollars. Apple plans for Shazam are unclear - probably they want to unite Shazam and iTunes, and maybe iPhones will have option of music's identification with using Siri virtual assistant.