Many of my friends have asked me for a tool to convert their large powerpoint presentations, word document,etc that are a part of their college work.
So below are the list of two sites that will do that for you.
1)ispeech
2)vozme 
The following is a great tool to extract the audio from any file format video
for more details click on the link below
Extract or Rip Audio from DVD, VCD, AVI, MPEG, MPG, DAT, VOB, MOV, FLV Videos to MP3
The following is a great tool to extract the audio from any file format video
for more details click on the link below
Extract or Rip Audio from DVD, VCD, AVI, MPEG, MPG, DAT, VOB, MOV, FLV Videos to MP3