There are lots of amazing photos of the twins on Flickr!  Some options:
  Seeing Double's Main Photostream 
  Our Favorite Flickr Uploads By Others 
  Iditarod 2012 ~ Berington Twins Media Finds (other non-flickr pics we've found and posted to Flickr)

Other useful picture resources:
  Iditarod's Offical Photo Page
  Alaska Dispatch Iditarod 2012 Photo Gallery 
  Anchorage Daily News Iditarod Photo Gallery