Flash would let you do it, I think.

Import the video to the library. Insert it onto the time line. Export it as an animated gif.

Not sure why you'd want a gif, though. The quality would either be painfully bad, or the filesize would be useless unless it's just for personal use on your hard drive or something... If it's for online use, you'd prolly be better off leaving it in SWF format (flash).