Ug, I'm late to this discussion, but I can't find anything in the Musicbrainz.org documentation that provides the same access / results as FreeDB.
In other words, from a "discid" (in Musicbrainz format or FreeDB format or otherwise), I want artist, album, and track titles, and optimally cover artwork.
Does anyone know how to get that, in JSON or XML format, from Musicbrainz?