Some online YouTube to MP3 converters are Flvto and YTD Video Converter. Flvto offers both an online converter and a desktop converter program. The free desktop converter is available for Windows and Mac OSX, and users can download it on the company's website.
The YTD Video Converter is available for Windows, Mac OSX, Android and iOS. The free version of this converter allows users to convert YouTube videos and videos from other popular websites to various formats, including MP3, WMV and AVI. In cases of an Internet connection interruption, this converter retries automatically and resumes its operation when a connection becomes available.