andree wrote: I wonder which player can read this M4B format in ppc device,

M4B is an audiobook extension of the regular audio M4P. if you load a m4b file in your ipod it will be seen as an audiobook, and not in the 'music' section, with convenient features like re-listening the last 30 sec or modify the speed of reading (1/2x or 2x) plus you can manage chapters within a file. There is some soft on the Net to do so and event to make such files from regular mp3 or else, like 'audiobook builder' on Mac OSX (http://www.splasm.com/audiobookbuilder/index.html)

hope this was helpful