American Mathematics Competitions - http://www.unl.edu/amc/
Organization that administers the AMC, the AIME, and the USAMO, with information about the contests, math problem archives, recommended reading lists, and other resources for students interested in mathematics. |
Australian Mathematics Trust - http://www.amt.canberra.edu.au/
Sponsors a number of competitions in the Australian continent. |
Crux Mathematicorum with Mathematical Mayhem - http://journals.cms.math.ca/CRUX/
Problem-solving journal at the senior secondary and university undergraduate levels. |
Math Competitions in USA - http://www.albanyconsort.com/contests/contests.html
Sample problems, information and links from multiple contests. |
Mathematics Archives - http://archives.math.utk.edu/contests
links to contests, problem sets, journals sites. |
Putnam Exam Information - http://www.math.harvard.edu/putnam/
Results from the Putnam competition, old exams, and problem archives. Includes problem of the day, selected from over 540 different Putnam, National or International Olympiad problems. |
Valentin Vornicu's MathLinks - http://www.mathlinks.ro
Math Olympiad Problem Solving site with a weekly contest, resembling IMO in difficulty, with a large math forum and downloadable materials. |