Here is a link to a list of lots of math contests at different levels:
http://www.mathcircles.org/content/math-competition-listing
The 2012 AMC 8 Contest will take place on Tuesday, November 13. The 2013 AMC 10/12 A Contest will take place on Tuesday, February 5. The AMC 10/12 B Contest will take place on Wednesday, February 20.
Here is a link to register for any of the three contests online
Encourage local colleges and universities to participate and offer the contests to interested and high-achieving students.Encourage schools and teachers in your area to participate in the AMC contests if they are not already doing so. Also, you can help prepare students (for instance in a math circle or club) by studying past contest problems available in AMC publications.