This is amazing! Basically, you enter in a search term and Yahoo! returns an RSS feed for all the MPEG files out there in Yahoo!land that match up. You then copy this RSS feed, go to iTunes, select Advanced—>Subscribe to podcast, and paste the feed in there. Next thing you know, iTunes is downloading videos for you to watch. Not all of the results will be ready to go straight over to your iPod out of the box, but it's still a pretty neat trick. I just found David Bowie's I'm Afraid of Americans video, featuring Trent Reznor, which I've been trying to track down for a while now. I presented a paper on it several years ago and need a copy for educational purposes. ;-) Unfortunately, it was a muxed MPEG1 file and wouldn't copy over to the iPod, so I'm looking into ways to convert it without losing the audio track.
Mad props to Thomas for sending in this tip!