http://www.fastclips.com/_s/fc_plyr_embed.swf?id=Xb66LQ8x73jH&date=2008/11/17&ttl=SingleLadies-Beyonce&JustinTimberlakeonSNL&idx=4&as=0&rel=1

My sister told me about this last month.  I finally found the full clip, not the best quality, but hilarious none the less!!