iLoveMP3 will quickly convert your whole MacOSX music library to mp3. It supports ogg, midi, aac or any other format that can be handled by quicktime or it's plugin. It uses LAME to recompress files, so the result should be superior in quality to iTunes "Convert to mp3". iLoveMP3 is also smart enough to skip mp3 files or files that already have an mp3 counterpart. Finally it will take advantage of dual processor machines by processing 2 files at once.