You Tube  that is.  Discovery Education (and the Discovery Channel and more) have a presence on this video sharing site.   To see what is available, go to:  http://www.youtube.com/user/DiscoveryEducation 

Or Teacher Tube perhaps.  For some Discovery Education related videos there, go to: http://www.teachertube.com/videoList.php?pg=videonew&tags=discovery&cid=16 

Also on Teacher Tube, check for the just created Texas DEN group at: http://www.teachertube.com/members/groupHome.php?group_id=TexasDEN