What if I say that you can get the audio used in a video and convert it to MP3. Yes it is true and possible.
No software to buy, download or install for it is just at the convenience of the world wide web. All you need to do is go to http://www.flv2mp3.com.
On the website just post the url of the location of the flv file or the youtube video and presto you will have the audio in mp3 format for download.
An easy way to get your mp3.