FLV to Mp3 Online Converter

Im looking for a script similar to these sites. [login to view URL], [login to view URL], [login to view URL] Visitors need to be able to input a url to a page with a video on it and it extracts the audio and creates an mp3 file for the person to download. The main website i would like it to be able to download from is youtube but it would be good if it would work with any page that has video on it. I do not require an upload function, i only want to allow the user to input a url to get the mp3. Id like it so that it gave the .mp3 file a good name so instead of giving it a random id but it isnt important. I do not need any other extra functions on it, just a basic enter url, wait a minute or two and then click the download link. I do not care if it is a script you already have or if you are going to make it, as long as it works.