If you want to rotate an array you can use a combination of shift()/push() or pop()/unshift(), depending on which direction you want to rotate. In your case shift/push will do.
This basic code illustrate how you can do that:
var mc1:MovieClip,mc2:MovieClip,mc3:MovieClip,mc4:MovieClip;
var mcs:Array = [mc1, mc2, mc3, mc4];
function rotateArray(els:Array):MovieClip
{
var el:MovieClip = els.shift();
els.push(el);
return el;
}
var nextEl:MovieClip = rotateArray(mcs);
Obviously, you also need to initialise and attach a click handler to your movie clips, here mc1, mc2 etc are just for illustration.
Check the AS3 Array docs for info on shift, push, pop, etc
To rotate left-wise:
shift() will pull the first element of an array and return it (while removing it from the array)
push() will put it back at the end of the array
To rotate right-wise:
pop() will pull the last element of an array and return it (also removing it from the array)
unshift() will put it back at the beginning of the array.