LAME
From LinuxReviews
LAME is a creat audio compressor which allows you to convert audio files to MP3 files.
Usage
Basic usage is simply
lame [options] <infile> <outfile>
See the lame manual page for a complete list of encoding options such as
lame -V0 -h -b 160 --vbr-new somefile.wav newfile.mp3