The video for 'Only' will be released tomorrow. Source. Source: The Sequel. I think I'll do some searching... Also, MySpace and NIN's record label, Interscope have teamed up to create a 'remix community' on MySpace Music. They will be releasing the necessary files, this time not only in GarageBand format, but Acid, Ableton, and something else.
You're not going to find the video. That was first posted on Echoing The Sound a few days ago. They would have found the video by now if it's out there somewhere. I don't know how to make remixes, but I hope they release the files for Only and other songs.