IDPA

Here is the IDPA website: http://www.idpa.com/

Blog author John Parsons is an IDPA member (A48372) who competes in various matches each year, mostly with his home club, The South East Idaho Practical Shooters in Idaho Falls, Idaho.

Here are the IDPA Rules:

http://members.idpa.com/Content/Rules/g0hunysc.eoc.pdf

Here are the IDPA Clubs in Arizona:

Phoenix Rod & Gun

Generally, PRG conducts an IDPA Match every Tuesday evening as well as the 3rd Saturday of each month.  The PRG IDPA also hosts a Classifier on the 4th Saturday of each month.

http://www.phoenixrodandgun.org/index.html

Prescott Action Shooters

PAS stages one monthly IDPA Match on the 4th Saturday.

http://www.prescottactionshooters.org/idpa.php?

Flagstaff Action Pistol

The Flagstaff group is Arizona's newest IDPA affiliated club.  Matches are staged on the first Saturday of each month.

http://northernarizonashootingrange.org/

Pima Pistol Club

IDPA matches are held the second Saturday and third Sunday of every month.
http://www.pimapistolclub.com/matches/idpa