If I told you that your computer could recognize songs just by listening to them you probably wouldn't believe me. If you use Tunatic though, you'll manage to do just that.
To make the application work the inbuilt microphone of your computer needs to be working or you need to have a microphone installed. Just run your media player and let the computer listen to your tracks. You'll have to click on the interrogation mark in the application window for the program to search its database. It lists the title of the song and the artist's name as soon as it finds it.
Obviously Tunatic doesn't get it right all the time, and depends hugely on the database of songs that is being maintained by the developers. It is still quite a surprising tool and can find certain songs really quickly.
Once Tunatic finds a song, it will also let you search iTunes for it, let you look for the ring tone, or search Google to find the lyrics.
Tunatic may not work all the time, but it is a really clever way of finding title's of all those unnamed songs in your library. Worth a try.