Center for Fine Art Photography (Colorado, but worth checking out) has 3 juried exhibitions.
1---June 18 - All Things Horse more info
2---July 15 - Our Environment, the good, bad and ugly more info
3---August 18 - International Exhibition of Fine Art Photography more info

August 31 deadline for Old World Wisconsin Photo Contest. All photos must be taken at Old World Wisconsin between September 1, 2007-August 29, 2008 more info
October 31, 2008 deadline for the Wet and Wild 2008 photo contest by Tamron. Win a Tamron lens!