I recently was searching for "offical" flag football rules and officiating information. What I discovered is just about every league plays by a slightly different set of rules (and I think some TEAMS even play by their own rules).
The best resource I found was NIRSA - The National Intramural-Recreational Sports Association. They have rule books, mechanics mauals, officiating videos and a basic test available at:
http://nirsa.humankinetics.com/produ...0spOffic#0foot
Other resources include the American Flag and Touch Football League at:
http://www.aftfl.com/
And the United States Flag and Touch Football League at:
http://www.usftl.com/
-Sean---