I just reviewed a neat little application that allows you to extract the audio from a video and save it as an MP3. The program is called Video mp3 Extractor and is offered as freeware from the good folks over at GeoVid.
The program installs quickly and easily. Though it doesn't have help files, it's very easy to use. Simply choose the AVI, ASF, or WMV file you want to extract audio from, and choose the location you want the program to save the MP3 to. Additionally, you can choose the quality and bitrate (up to 320 kbps) then click the Start button. It's that easy.
It's a nifty little tool to have on hand. If you enjoy using it, please contact the author and let them know how much you appreciate their freeware.