TubeSock 1.0 from Stinkbot grabs YouTube videos from the web and copies them to your video iPod, Mac, or PlayStation Portable.
TubeSock knows how to convert the video using the codecs and bitrates best for each device. It can even add the video to iTunes for you.
TubeSock can play back YouTube videos directly. Just copy & paste the YouTube URL, and TubeSock will play the video for you.
TubeSock can also grab just the audio portion of a video and add it to iTunes, too. Find your favorite tracks, outtakes, and live recordings on YouTube, then just click “Save” to copy them to your iPod. The conversion is quick and there’s no loss of audio fidelity.
TubeSock costs $15. Until you register, TubeSock will convert only the first 30 seconds of a video.
More info and download link here.