The programs they talk about in the link below but SOX and Sound Converter
can't convert to MP3. The description in Synaptic says that both of these
can do it but I have already DLed and tried both of them. In the docs for
SOX it mentions a big list of audio formats it can handle but MP3 is not one
of them.

http://ubuntuforums.org/showthread.php?t=220313