Just follow this easy steps:

sudo aptitude install vorbis-tools faad pythonmkdir $HOME/conversion/ cd $HOME/conversion/wget http://stuff.zarate.net.ve/m4b2ogg.pychmod +x m4b2ogg.py

Having done this… all you need to do is put your files inside the conversion folder under your /home/< user >/conversion and the program will do the work

Source: http://robert.penz.name/94/convert-m4b-to-ogg-on-linux/