ffmpeg2theora - http://v2v.cc/~j/ffmpeg2theora

with ffmpeg2theora you can convert any file that ffmpeg can
decode to theora. right now the settings are hardcoded into
the binary. the idea is to provide ffmpeg2theora as a binary
along sites like v2v.cc to enable as many people as possible
to encode video clips with the same settings.

usage right now:
 ./ffmpeg2theora clip.avi
 will produce clip.ogv
 for more options run ffmpeg2theora -h

 there is a export plugin for kino (http://kino.schirmacher.de/)
 more info in kino_export/README

 subtitles can be embedded in an ogg stream, see subtitles.txt for more info.