MARF is a general cross-platform framework with a collection of algorithms for audio (voice, speech, and sound) and natural language text analysis and recognition along with sample applications (identification, NLP, etc.) of its use, implemented in Java.
Basing on the MoodLogic(c) idea, Open SONG db will be the free alternate!
It will scan your harddisc for mp3s and then check them online for more detailed information.
You will (if somebody else already added this song to the library) get the song's sp