Fingerprinting Client have posted some more about their work on a fingerprinting client that looks up track metadata based on audio and tag analysis. The client can be downloaded from the middle of that post: it's run from the command line, with the file to be analysed as the first argument, and produces XML results like this:

<!DOCTYPE metadata SYSTEM "">
<metadata fid="14890790" lastmodified="1205776219">
<track confidence="0.762396">
    <artist>DJ Donna Summer</artist>
<track confidence="0.139232">
    <artist>Donna Summer</artist>
<track confidence="0.098371">
    <artist>DJ DONNA SUMMER</artist>
    <title>04 (Boomshakalaka)</title>

Note the confidence level, which is very useful.

As Norman Casagrande pointed out in response to Yves Raimond's post about identifiers, using the -nometadata parameter gives you just the internal identifier for each track (fid in the example above), and the alternative spellings for that track's metadata can be retrieved from{ID}.xml, which can also be generated using the -url parameter.