MusicBrainz is here to help you with your music selection:

MusicBrainz, an open-source music meta-data service, has announced the formal launch of its music recognition service designed to provide an open standard for recognizing
and identifying digital music files, while providing an alternative to costly
proprietary offerings. Supporting this effort, the project announced a number
of service sponsors including Relatable® LLC and AgentArts, Inc.

MusicBrainz and its sponsors are creating a "music information commons" where the online music community creates and maintains a public database of
information about music, enabling definitive recognition of digital music
files and audio CD's. In development since 1998, MusicBrainz now contains
over 650,000 music tracks based on contributions from its community of over
2,000 contributors. This coverage continues to grow as consumers use the
MusicBrainz file tagger to identify their digital music files and grow the
shared MusicBrainz database.

"Currently there is no free and universally accepted digital music meta-data
available to the online music space, and the very few commercial companies who provide this resource offer their services under highly restrictive and
expensive licenses. It is our belief that a universal standard for digital music recognition is simply too important and valuable to all online music services to be monopolized by any one company. We also believe that online music consumers would much rather contribute to a truly open source resource,"
said Robert Kaye, founder of MusicBrainz.

You can download the actual database here. More on the concept:

MusicBrainz is a user maintained community music metadatabase. Music metadata is information such as the name of an artist, the name of an album and list of tracks that appear on an album. MusicBrainz collects this information about music and makes it available to the public so that music players can retrieve information about the music that is playing. For instance, an audio CD does not contain the name of the artist, album or a listing of the tracks. A music player can use the physical characteristics of an audio CD to lookup the correct metadata for the CD and show it to the user during playback.

MusicBrainz also takes this concept one step further in applying it to digital audio files like MP3 files and Ogg/Vorbis files. The metadata contained in these files is often incorrect or missing altogether. If this data is not present or correct, it makes it difficult for users to find the music they wish to play. Many MP3 lovers have a huge collection of MP3 files but often have a hard time finding the music to which they want to listen. The MusicBrainz solution for this is the MusicBrainz Tagger, a Windows application that uses acoustic fingerprints (TRMs) to semiautomatically identify tracks in your music collection and then write clean and accurate metadata to your music files.

The MusicBrainz web site provides a catalog of music data that is known to MusicBrainz. Please understand that MusicBrainz only provides the data about the music and not the music itself. MusicBrainz does not condone copyright infringement and thus cannot help you find the best place to illegally download copyrighted works.