By the way, although the 4 kbps vorbis encoder isn\'t publicly available yet, the existing encoder ( 
http://sjeng.org/vorbisgt3.html ) can encode files at around 8.5-9.5 kbps (depending on complexity of the audio).  There\'s a resampling option and I resample to 8 kHz and then use quality -1.  Awesome!!  I can now encode low bitrate audio books for my Zaurus.   The quality of the 9 kbps stereo voice files aren\'t yet as good as the 5 kbps mono RealAudio voice codec, but since vorbis is open-source I\'m sure it will get there someday. 
In any case that\'s MUCH better than the 32 kbps mp3 audio files I would\'ve had to otherwise create.  (Yes, Zaurus can play 32 kbps mono MP3 files.  My desktop can play 8 and 16 kbps mono MP3 files, but the Zaurus can\'t... yet)