"Down to the Sea with Paper & Pen"
WHO? One of the biggest organizations for teen writing, with the possible exception of The Alliance for Young Writers & Illustrators. Very reputable, very big deal. Curtis Sittenfeld, of Prep fame, wrote for them when she was a WriTeen.
WHAT? A writing contest for a full scholarship to their writing "camp" in New England.
HOW? They have a specific submission form, check the website for details.
MORE INFO? http://www.merlynspen.org/contentmgr/showdetails.php/id/39543