at home at http://www.musicbrainz.org
http://musicbrainz.org/doc/HowPUIDsWork -- PUIDs are universal identifiers for a piece of music http://blog.musicbrainz.org/archives/2006/03/finger_fingerpr.html -- more fignerprinting http://users.musicbrainz.org/~matt/python-musicbrainz2/html/ -- python interface to musicbrainz http://musicbrainz.org/doc/XMLWebService -- webservice in general