Useful links

Math competitions: General IMO site: http://imo.math.ca/
Science olympiads (math): http://olympiads.win.tue.nl/imo/
IMO Compendium: http://www.imo.org.yu/
Internet resources: MathLinks: http://www.mathlinks.ro/
Art of Problem Solving: http://www.artofproblemsolving.com/
Other: IMO scores statistics: http://www.srcf.ucam.org/~jsm28/imo-scores/
DIC picture gallery: http://www.dic.si/Galerija/thumbnails.php?album=34