You can use Free Flash Flv MP3 Converter to do this. It's a powerful tool to convert Flv files to MP3 files. And Free Flash Flv MP3 Converter can convert batches of Flv to MP3 at one time. This Free Flv to MP3 converter is quite easy-to-use and completely Free!
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How to use
Free Flash Flv to MP3 Converter.
