From Hoo Technologies:
FLV MP3 Converter converts FLV to MP3 and MP3 to FLV. The program supports the latest version of FLV file including FLV on YouTube, Google Video, Yahoo Video, and so on.
FLV MP3 Converter is also an ALL IN ONE audio converter that supports more than 100 audio and video files, and convert file to major audio formats, for example, MP3, WMA, AAC, M4A, M4B, OGG, APE, FLAC, WAV, AIFF, MPA, and so on. The program is a professional audio converter that enables you customize encoding codec, sample rate, bit rate, channels, and volume as you like.