Mp3:
Mp3 is a universal audio format, playable on iPods, computers, media players and
mobile phones.
Mp3 is a compressed format, allowing smaller filesizes, offering faster download times and requiring less storage space on players, but at some expense to the audio quality. Many listeners can't really hear the difference between mp3 and full CD-quality audio, and hence its convenience has lead to it becoming the default option for audio.
Our albums are generally encoded at around 256kbps (sometimes with VBR), balancing optimal audio quality without blowing out filesizes excessively. We encode using the Fraunhoffer algorithm, which preserves more detail in the human audible range than the lame encoder.
Our mp3 files are free of any DRM (digital rights management), so you can transfer them to any of
your media technology. You've paid for them, they're yours for your personal use without
restriction.
Mp3 files can be burned to disc, either as an mp3 disc, or an audio CD after converting them to a standard audio (.wav or .aif) format first.
FLAC:
FLAC is a high-quality audio format, allowing CD-resolution audio. It is ideal if you wish to burn your files to a CDR, or listen over a high resolution audio system. However files usually require special decoding by the user before playing or burning to disc.
FLAC (Free Lossless Audio Codec) is a LOSSLESS compressed audio format. This means that it preserves the full audio quality of a CD, but optimises the filesize for downloading. Typically, file sizes of
around 60% are achieved without any degradation or loss of audio quality from the source files
at the CD standard of 16bit/44.1kHz.
Obviously the file sizes are larger than for the mp3 version - usually around 300-400Mb for an
album, compared to 100Mb for an mp3 album.
In addition, you'll need to know what to do with the files once you've downloaded them. In most
cases you'll want to decode the files to wav or aiff, either to import into programs like
iTunes, or burn to CDR. Some programs will play flac files natively.
There is a lot of information about flac online (eg:
http://flac.sourceforge.net/)
Alternate audio link 
