The United States Curling Assocation (USCA) hosts national championships each year. The Mens and Womens even was February 9th -16th,2013 in Greenbay, WI. (website - http://www.2013usacurlingnationals.com/)
Anyone can watch recaped highlights at Universal Sports. Full matches if you subscribe to dish network. (Sorry, Time Warner does not support Universal Sports).
The winners (Clark and Brown) of these events will play in the World Curling Championship held in Victoria, British Columbia, CA Mar 30, 2013-Sun Apr 7, 2013 for the Men. (website - http://www.curling.ca/championships/worlds/ ) and Riga, Latvia March 16th-24th for the Women. (website - http://wwcc2013.curlingevents.com/home).
The Winners will also be one of 4 seeds playing down for a spot on the US Olympic Team in November 10th-17th in Fargo, ND. (Background Into - http://www.teamusa.org/Media/Games/2014/Preview/Team-USA/Curling.aspx)
USCA Press Release for Women (PDF)
USCA Press Release for Men (PDF)
You Tube interviews