This is an easy one! You do not have to "qualify" in any way to join. Just send money! An application form can be found at http://members.tridpod.com/~whitemountainmilers/member.htm
There are many places where this information can be found. We list as many as we think are relevant to our general area. However, we know that you may be searching for something beyond our scope. If so try www.coolrunning.com - not only do they list the races, they also post the results and sometimes have on-line applications.
You can email the Webmaster/Publicity Poobah at firstname.lastname@example.org - if she doesn't know the answer she'll fake it.
or the Co-presidents at email@example.com - if they don't know the answer they will refer you back to the Poobah!
This year the 1/2 Marathon is October 31st. Unfortunately it closed at 400 runners. Please come volunteer!