setInterval.

var myInt;
startInterval();
var who:Array = new Array("He","She","I","ME");

function startInterval(){
  clearInterval(myInt); // clear the interval, to make sure you dont over lap...which has interesting results ;)
  myInt = setInterval(this, "myFunction", 1000);
}

function stopInt(){
  clearInterval(myInt);
}



function myFunction(){
    var randomNum:Number = Math.floor(Math.random() * (3 - 0 + 1)) + 0;
 trace( who[randomNum]+" likes to Move it , Move it");
}