Math Olympiad: have both elementary amd middle school divisions
http://www.moems.org/

Mathcounts - for 6-8 grades but you can start preparing early
http://www.mathcounts.org/

Rocket City Math League:
http://www.rocketcitymath.org/index1.htm

I am resurrecting this thread as registration is now in progreass for Math Kangaroo 2008.
Check the top of this thread, go to www.mathkangaroo.org or just e-mail me with any questions.
The competition is open to students in grades 2-12.
Check it out. It is administered by a non profit organization.
Ania

Ania:
I'm assuming that the child should register to take the test in the grade they are enrolled in, whether accelerated or not. My son should be in first grade (chronologically) but attends 3rd grade math, 2nd for everything else. Would he register for the 3rd grade level test or 2nd?

Hmm, good question Debbie! And thanks for the link Ania, I'm definitely interested, but doubt it would work out on a school day. DS is in a simiilar situation chrono 3rd, in 5th with 6th grade math.

From what the website said, it looks like the child should take the level of math s/he's currently taking, not the chronological age/grade level.

Of course, if you're bound and determined for the kid to win some cash, then I guess you could go with chronological grade level instead, to try to boost his/her chances...

For a child who has been grade skipped you have no choice but to register them for the grade they are currently in, but for a child who is only math accelerated, while remaining with his age peers for other classes, the choice is yours. There are no advantages in registering them for higher levels, the test is not easy - very non standard questions, they have to use logic and combinatorics, not just simple arithmetic.
So Debbie, you can register your child for level 2, Dottie for level 5.
The test takes place in the evening, check out if there are locations near you, if no you can open your own site for example in a public library. I did just that two years ago and that is how we started.
Will be happy to answer more questions :-)
Ania

Sadly Math Kangaroo is during our school district's spring break this year, so we won't be participating. We already do Continental Math but the Rocket City one looks good. Math counts has always been on the same weekend as Science Olympiad, but I talked to them yesterday and they said they're going to change the day this year.

We had something like a math club afterschool a few years back and unfortunately it dwindled. Hopefully we can get it back up and going (I'll ask the teacher-sponsor today).

Bump...
Since there are so many new members on this board...

There is still time to register for Math Kangaroo 2008
Go to www.mathkangaroo.org

Hello Again:

Registration deadline for Math Kangaroo 2008 has been extended till the end of December.
And honestly, they don't pay me anything for promoting this :-)

I started this competition in our state two years ago and it has grown so much, that next year we are probably going to have it at the state University!
If there is no location near you, you can PM me and I will tell you what to do to start your own chapter.

For more info go to www.mathkangaroo.org