Here is the command line to convert a DVD vob file into FLV flash video with ffmpeg :
ffmpeg -i VTS_01_1.VOB -b 256000 -er 4 -ar 44100 -ab 96000 -f flv -s 570×456 -acodec libmp3lame -vol 1024 my_video.flv
"First they ignore you, then they laugh at you, then they fight you, then you win." [Mahatma Gandhi]