www.isabio.com

I just found out about it today through MathKangaroo. They are one of this year sponsors.
From what I gather it is like a tutorial/competition prep service based in Chicago, but they do have an online league that runs all year (yes, thorough the summer too!). I am fascinated.
Start by reading their articles, which they call columns. Very good! And they believe in AoPS, which I, as you know, adore.
This is for middle schoolers and up.
Let me know please what your impressions are:-)

http://www.isabio.com/?_csq=64

This is the link to their weekly contest site. Looks like they follow each contest with detailed solutions!

Thanks Ania and keep those recommended resources coming! I just signed my kids up for an online writing course that you posted here about a month ago.

http://www.writeguide.com/

I appreciate your suggestions greatly!