Introduction to Competitive Programming
chrisjrn writes "Last year, I unexpectedly found myself entered in the Australian Computer Programming Competition, and somehow did well in it. As a result I decided to write a guide as an introduction, for high school-level students (and others, I suppose,) into the world of programming competitively based on my experience, and how to go about successfully competing in competitions." Article looks like a good start, I'm sure Slashdot readers can add many more tidbits of wisdom.
When I was in high school the competitions were conducted in ugh Pascal. It shifted to C after I graduated. If you can pick a language why not use perl with all of cpan at your disposal you should be able to crush the competition.