http://mediautils.garage.maemo.org/tablet-encode.html
A bloody handy little perl script called tablet-encode which automatically transcodes video files into a good format for the Nokia tablets. Even has a GUI (which doesn't work for me) through gtk2-perl. :)
http://www.linuxquestions.org/questions/linux-general-1/mplayer-and-mencoder-the-dvdmovievideomp3-player-and-encoder-for-linux-616681/
How to save mms, wmv, and lots of other streaming goodies as standard output files on Linux using mplayer and mencoder.