It is an audio converter that can convert WAV to MP3 in a few seconds by using Lame codec. You can adjust bit-rate and other sound aspects to get great quality/size files.
MP3Coder includes, as secondary functions, an ID3 tags editor for your MP3 files and access to FreeDB Internet data base, where you will find all the information for your music (artist, album name, year, genre, etc.)