no doubt u can do it in vcd cutter but exact mp3 length cannot be figured out. u ve to first cut the video upto which u want the mp3.so u can do it in winamp itself but the cut music will be in wav format. but never mind u can convert it into mp3 in db power amp converter later on . to do this go for the music plug in output inside winamp and change the plug in to Null soft . close it play the desired movie file . u cannot hear any sound but music is being stored in c drive . so to cut music preferentially ,forward the movie in pause and play when to start and stop. to play back in winamp again change the plug in in output to direct sound . convert the wav file to mp3.
DIFFICULT JOB BUT WORTH TRYING..