Convert MP4 to MP3

Have you ever downloaded a music video with DownloadHelper from Youtube.com but don't know how to play it in your portable music player or set it a ringtone of your phone? I've found a small and easy-to-use freeware that can convert MP4 video files to MP3 audio files (more precisely, it converts a wide range of video files to MP3, including MPEG, AVI, MOV, FLV, DVD, VOB). It is simply called Convert MP4 to MP3, which can be downloaded here. Thank My Digital Life for the pointer.