Latest video files come in different formats. Some of the programs and devices are compatible with only a few formats and this requires you to convert files between different formats frequently. Lot of streaming files on the internet are in FLV or MPEG format and to use them on your portable devices you may need to convert them into MP3. To do this you will be needing a application called VLC media player. VLC is the most powerful open source medial player which almost supports all of the video formats. Download and install this application. Open the player and open the FLV file from the file menu. In the same open source menu at the bottom check the 'Streaming and Saving' option and go to the settings beside it. There you can choose the format you want to convert the file to. This video shows how to convert FLV or MPEG files to MP3 format.