Streets of Willow Springs – where to register?

I want to take my bike (for the 1st time) to the Streets of Willow Spring this summer sometime.
I noticed that you need to be part of a group that organizes Track Days, a club or something.

I only found this: Motoyard.com Motorcycle Track Days - March 14th, 2010 @ Willow Springs - 2.5 Mile Road Course

and this: TrackDaZ

Do you have any recommendation?

Thank you.

Been with TrackDaZ a few times and they're cool. I don`t know motoyard but I hear they're super cheap (don't know if it means poor organization though). Most of these orgz in SoCal will run about the same format so I would pick the cheapest one...

Check this thread, lots of good info: http://www.600riders.com/forum/usa-pacific/27173-2010-socal-track-days-who-where-when.html
And post your dates in there as well... Cali Rider and I will go to WSIR (big Willow) most likely around end of March early April, and again this summer...