VidtoMP3.com is one of the few sites that performs the video to MP3 conversion on their servers. The time it took to convert my video was rather short and the site is relatively light on advertising.
It seems the download link is only displayed once which is a slight annoyance.
Because the conversion process from Youtube video to MP3 is working well, VidtoMP3.com deserves a recommendation.
Apart from the ubiquitous Youtube, VidtoMP3.com also supports MegaVideo, Dailymotion, Metacafe, Veoh, Myspace, Break, iFilm, Bolt, ClipJunkie, ClipShack, CollegeHumor, FunnyJunk, Glumbert, GoFish, Grouper, Hallpass, MilkandCookies, Putfile, SantaBanta, Sevenload, Sharkle, Shoutfile, Vimeo, vSocial, Yikers, ZippyVideos.