USA Computing Olympiad WinnersThe USA Computing Olympiad (USACO) is for middle and high school students interested in computer programming. The USACO holds six Internet competitions during the school year and a proctored test (the U.S. Open) in the spring. The top 16 are then invited to an all-expense-paid summer training camp, and four from the camp are picked to be on the state team at the International Olympiad in Informatics.
To sign up for the USACO listserv, go here. The Web site also provides a helpful Training Page for more practice. You can also take a look at the competition and winners dating back to 1992. There's also a Discussion Board.