The deal is good for the entire month of September, which happens to be National Chicken Month (they're calling it "Love that Chicken! Month").
The deal is available at participating Popeyes locations nationwide.
Of course, if you're in the SoCal area, Popeyes regularly offers two pieces of fried chicken (leg and thigh) for $1.29 on Tuesday and Thursdays (it used to be even cheaper at 99 cents!).