Windows 7 Tip: 
Flv Crunch is a very easy to use and free video converter for your Mac. Flv Crunch can accept as input: MPEG 1 (.mpg), MPEG 2 (.vob), MPEG 4 (.mp4), Quicktime (.mov), Cell Phone videos (.3gp), Windows Media Player files (.wma, .wmv), RealPlayer files (.ra, .rm) *rv10 video codec only , Divx AVI (.avi), Digital Video (.dv), MP3, and AAC files. Flv Crunch can convert input files into: MPEG 1, MPEG 2, MPEG 4, Quicktime Mov, 3GP, Digital video, Windows Media Video (wmv), Divx AVI, MP3 (audio only), and AAC (audio only).
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Who would want to use this program? Anyone who likes watching digital video on their computer, iPod, iPhone, Apple TV, DVD player, PDA, or any other device. You could turn a video you downloaded from YouTube into something you can use with iMovie, iDVD, iTunes, Quicktime Player, and others.
This software is okay. But I much prefer VideoMax Free Video Converter Freeware. It has more sets.