Checked out the 2007 article Top Ten Online Converters - Freakitude, and four of them still work:
"1. ZamZar: Free Online file conversion service. It can convert your online videos to a number of video formats. The converted files are sent via email.
2. Tubefish : Tubefish video converter can convert your videos instantly to MPEG, AVI, MOV, 3GP and Divx.
3. Movavi : Movavi is another online video converter. It notifies via email when converted files are ready to download."
Here are three more, from 13 Useful Free Online Video Converters | Flash, Design, Vector, Photoshop, Adobe Tutorials | GraphicMania.net:
- FLVto.com: Converts or downloads Youtube videos to MP3, MP4, AVI or MPEG.
- You Convert It "Convert any Youtube and other Online Video to popular formats or download the video without buying or installing anything on your PC"
- Tubeminator: Download and convert from any site. FLV, AVI, MP3, MP4