Abcde - A Better CD Encoder - Frontend. Grabs an entire CD and converts each track to MP3, then ID3-tags each file, with one command. - http://lly.org/~rcw/abcde/page/
dekagen - Bourne shell script that automates the ripping, encoding, and naming of music data that comes from CDs and is saved in an MP3 or an OGG file. Frontend to several programs (required), for LINUX and other UNIXes. - http://www.mbayer.de/dekagen/
LAME Project - Educational tool to be used for learning about MP3 encoding. LAME aims to be the basis of a patent free audio compression codec. - http://lame.sourceforge.net/