According to Nikon: "The Nikon Photo Contest International has been held by Nikon since 1969 and its aim is to provide an opportunite for photographers around the world to communicate and enrich photographic culture for professionals and amateurs alike."
There are two categories for this year's event: a "free" category (Category A) and "Energy" (Category B). The second category, says Nikon, "...invites applicants to submit images that capture the energy and sights and subjects that inspire, motivate or excite them or viewers."
Entry dates for the contest run from September 1, 2010 until November 30, 2010. You can submit up to two images in each of the two categories (for a total of four photos). Prizes, as you might expect, include lots of Nikon cameras and you can find a full list of them and all of the official rules here.